Emergency chemical hazardous substances(AHOV)

emergency hazardous substance chemical

Among emergency situations technogenic nature Accidents at chemically hazardous facilities occupy one of the most important places. The chemicalization of the industrial industry in the second half of the twentieth century led to an increase in man-made hazards associated with chemical accidents, which may be accompanied by significant emissions of chemically hazardous substances (CHS) into the atmosphere. material damage and great loss of life.

About 7 million poisons have been synthesized in the world. 60-70 thousand of them are in contact with humans.

Emergency chemically hazardous substances is a new term assigned to a group of hazardous chemical substances, which for over three decades in civil defense were called highly toxic substances (SDYAV).

In civil defense, the term “potently toxic substance”, together with the abbreviation SDYAV, was introduced in the mid-60s. In the materials of the Ministry of Defense, SDYAV had the following definition:

“SDYAV are substances used for national economic purposes, which, when released or spilled, can lead to air contamination and cause mass casualties of the population, as well as personnel connections and parts." This definition includes ammonia, chlorine, sulfur dioxide, phosgene and a number of other substances similar to them in physical and toxic properties.

During the period of use of the term “potently toxic substance,” attempts were made repeatedly to determine a list of hazardous chemical substances (HCS) in order to solve practical problems of protecting the population in emergency situations.

In the mid-80s of the last century, the USSR Civil Defense Headquarters, together with the Ministry of Chemical Industry and the Ministry of Health, developed a list of chemical substances of 107 items. At the same time, along with ammonia and chlorine, the list included substances such as methanol, dichloroethane and a number of others that pose the greatest danger to the body during internal consumption and are not capable of forming a source of mass destruction with short-term inhalation exposure.

In addition, such substances and work with them were under the control of the labor protection service. Therefore, at the end of the 80s, new criteria were developed for classifying chemical substances as SDYAV, which led to a reduction in the list of SDYAV.

According to the “Temporary List of Potent Toxic Substances” of 1988, 34 substances are classified as toxic substances that pose a real danger and can cause emergencies in case of accidents.

These are acrylonitrile, acrolein, ammonia, acetonitrile, acetone cyanohydrin, nitrogen oxides, hydrogen bromide, methyl bromide, dimethylamine, methylamine, methyl acrylate, methyl mercaptan, hydrogen arsenic, hydrogen sulfide, carbon disulfide, sulfurous anhydride, hydrochloric acid, hydrocyanic acid, trimethylamine, phosgene , phosphorus trichloride, phosphorus oxychloride, fluorine, hydrogen fluoride, chlorine, chloropicrin, hydrogen chloride, cyanogen chloride, methyl chloride, ethyl mercaptan, ethylene amine, ethylene sulfide and ethylene oxide.

This list includes only those chemical substances that, due to their high volatility and toxicity, can cause mass casualties in emergency situations.

However, in 1991, taking into account the scale of use of substances, the list of toxic substances was revised. The number of SDYAS has now been reduced and brought to 21. Substances that are rarely found or used in small quantities and in case of accidents that do not pose a danger to the population are excluded.

In 1994, instead of SDYAV, GOST R 22.0.05-94 introduced the term “hazardous chemical substance”.

A hazardous chemical is a chemical, direct or indirect, whose exposure to humans can cause acute and chronic illness or death.

This term turned out to be not entirely successful, since this class of substances includes all harmful substances used in industry, a significant part of which does not pose a danger in emergency situations.

Accidents that have occurred in recent years at chemically hazardous facilities have shown that emergency situations can arise not only as a result of the spread of chemical substances in the atmosphere, but also when they are discharged into water sources. Previously, this problem was of secondary importance.

Thus, there was a need to highlight new group substances, which by its definition must be different from the SDYAV group. In this case, the greatest danger is posed by chemical substances that have a high boiling point and good solubility in water.

Based on the above, it became necessary to separate from the list of chemical substances from the group only those hazardous substances that, in the event of an accident, could lead to an emergency situation. Therefore, GOST R 22.9.05_95, taking into account modern international terminology, introduced a new term “emergency chemically hazardous substance”. This standard defines this term as follows.

Emergency chemically hazardous substance - hazardous chemical used in industry and agriculture, in the event of an emergency release (spill), the environment can be contaminated in concentrations that can affect a living organism (toxodoses).

So, hazardous chemicals cover only that group of substances that may pose a danger in emergency situations.

According to the possible route of penetration into the human body, hazardous substances are divided into substances:

Inhalation action (AHOV ID) - when entering through the respiratory system;

Oral action (HAV PD) - when administered through the mouth;

Skin-resorptive action (AHOV KRD) - when exposed through intact skin.

An emergency chemically hazardous substance of inhalation action is an emergency chemically hazardous substance, the release (spill) of which can cause massive injury to people by inhalation.

Thus, the term SDYAV was replaced by a new term - AKHOV ID. However, using the full abbreviation AHOV, taking into account the route of its penetration into the body, creates inconvenience when pronouncing, as well as when preparing documents. Therefore, in practice, they use an abbreviated abbreviation without the prefixes ID, PD, KRD.

It is quite difficult to unambiguously determine the list of all hazardous substances due to the fact that it depends not only on the physicochemical and toxic properties of these substances, but also on the conditions of their production, storage and use.

In some guidance documents on issues of civil defense and safety in emergency situations, in addition to the hazardous chemical substances listed above, the most common hazardous substances are classified as emergency chemicals: rocket fuel components; toxic substances (mustard gas, lewisite, sarin, soman, Vi_Ex); methyl isocyanate; dioxin; methyl alcohol; phenol; benzene; concentrated sulfuric acid; aniline; toluene diisocyanate; metallic mercury.

Of all the hazardous chemicals currently used in industry (more than 600 thousand items), only a little more than 100 can be classified as hazardous chemicals, 34 of which are most widespread.

During an accident, hazardous substances are released into the atmosphere, forming a contamination zone. Moving in the direction of the surface wind, a cloud of hazardous substances can form infection zone up to tens of kilometers deep, causing damage to people in populated areas.

The largest consumers of chemical chemicals:

• - ferrous and non-ferrous metallurgy (use chlorine, ammonia, hydrochloric acid, acetone cyanohydrin, hydrogen fluoride, acrylic acid nitrile);
• - pulp and paper industry (use chlorine, ammonia, sulfur dioxide, hydrogen sulfide, hydrochloric acid);
• - mechanical engineering and defense industry (use chlorine, ammonia, hydrochloric acid, hydrogen fluoride);
• - public utilities(use chlorine, ammonia);
• - medical industry (use ammonia, chlorine, phosgene, acrylic acid nitrile, hydrochloric acid);
• - agro-industrial complex (use ammonia as a refrigerant for refrigeration units).

Thousands of tons of hazardous chemicals are transported every day various types transport, pumped through pipelines. All of the above-mentioned economic objects are chemically hazardous.

Danger level for the population of each chemically hazardous facility is determined by its category. The criterion for classifying an object into a particular category of chemical hazard is the number of people falling within the zone of possible chemical contamination HOV:

The ability of substances to cause poisoning (intoxication) of the body is called toxicity . It is characterized by the concentration of a substance in the air (mg/m3), as well as the dose (mg/kg of weight) that causes varying degrees of poisoning of living organisms.

There is an average lethal toxodose, which causes fatal outcome in 50% of those affected, as well as an average damaging (incapacitating) toxodose, which causes poisoning in 50% of people entering the zone.

Classification of hazardous substances is carried out according to various criteria

The ability of any hazardous chemical substance to easily pass into the environment and cause mass destruction is determined by its basic physicochemical and toxic properties.

The most important physical and chemical properties are:

state of aggregation,

solubility,

density,

volatility,

boiling temperature,

hydrolysis,

saturated steam pressure,

diffusion coefficient,

heat of vaporization, evaporation temperature, freezing point,

viscosity,

corrosiveness,

flash point and ignition temperature, etc.

In most cases, under normal conditions, hazardous chemicals are in gaseous or liquid states. However, during production, use, storage and transportation, gases are usually compressed into a liquid state, which sharply reduces the volume they occupy.

Classification of hazardous chemicals according to basic physical and chemical properties and storage conditions

	Characteristics	Typical representatives
	Liquid volatiles stored in containers under pressure (compressed and liquefied gases)	Chlorine, ammonia, hydrogen sulfide, phosgene, etc.
	Liquid volatiles stored in containers without pressure	Hydrocyanic acid, nitrile acrylic acid, tetraethyl lead, diphosgene, chloropicrin, etc.
	Fuming acids	Sulfuric (1.87), nitrogen (1.4), hydrochloric (1.15), etc.
	Bulk and solid non-volatile when stored at temperatures up to 40 o C	Sublimate, yellow phosphorus, arsenic anhydride, etc.
	Bulk and solid volatile when stored at temperatures up to 40 o C	Salts of hydrocyanic acid, mercurans, etc.

The most common classification of hazardous substances is carried out based on the predominant impact on humans. In accordance with this criterion, the classification of hazardous chemicals is divided into the following six groups:

first group- substances with a predominantly asphyxiating effect (chlorine, phosphorus trichloride, phosgene);

second group- substances with predominantly general toxic effects

(hydrogen cyanide, cyanogen chloride, hydrocyanic acid, carbon monoxide);

third group- substances that are asphyxiating and generally poisonous

action (hydrogen sulfide, nitrogen oxides, sulfur dioxide);

fourth group- neurotropic poisons, that is, substances that infect

central nervous system (organophosphorus

compounds, carbon disulfide);

fifth group- substances with asphyxiating and neurotropic effects (ammonia);

sixth group- metabolic poisons that affect the central nervous system and hematopoietic organs (dichloroethane, ethylene oxide, methyl chloride).

It should be noted that this classification is to a certain extent arbitrary, since most hazardous chemicals affect the human body comprehensively, In addition, in addition to the main effects, there are side effects, often very significant.

Depending on durability Manifestations of toxicity in the atmosphere and on the surface of chemical substances are distinguished:

• - unstable(stored up to 1 hour);
• - persistent(stored for more than 1 hour).

Depending on the speed of action:

• - fast-acting(clinical manifestations appear within 1 hour);
• - slow-acting(clinical manifestations appear later than 1 hour).

Accordingly, the centers of action of the chemical agent in terms of durability and speed of action can be:

• - fast-acting, unstable (ammonia);
• - fast-acting persistent (organophosphorus compounds);
• - slow-acting, unstable (phosgene);
• - slow-acting, persistent (nitric acid).

Routes of entry of substances into the human body, distribution and transformation of harmful substances in it, action harmful substances

Rapid development chemical industry and the chemicalization of the entire national economy led to a significant expansion of the production and use of various chemicals in industry; the range of these substances has also expanded significantly: many new chemical compounds have been obtained, such as monomers and polymers, dyes and solvents, fertilizers and pesticides, flammable substances, etc. Many of these substances are not indifferent to the body and, when released into the air of working premises, directly on workers or inside their bodies, they may adversely affect the health or normal functioning of the body. Such chemicals are called harmful. The latter, depending on the nature of their action, are divided into irritants, toxic (or poisons), sensitizing (or allergens), carcinogenic and others. Many of them simultaneously have several harmful properties, and above all, toxic to one degree or another.

Harmful substances may have local And general action on the body.

Local action most often manifests itself in the form of irritation or a chemical burn at the site of direct contact with the poison; This usually occurs on the skin or mucous membranes of the eyes, upper respiratory tract and oral cavity. It is a consequence chemical exposure an irritating or toxic substance to living cells of the skin and mucous membranes.

General action poison occurs when it penetrates into the blood and spreads throughout the body.

Some poisons have specific, that is, a selective effect on certain organs and systems (blood, liver, nervous tissue, etc.). In these cases, penetrating the body in any way, the poison affects only a specific organ or system. Most poisons have general toxic action or effect simultaneously on several organs or systems,

The main routes of entry of harmful substances into the body are respiratory tract, digestive tract and skin.

The greatest importance is their entry through respiratory system. Toxic dusts, vapors and gases released into indoor air are inhaled by workers and penetrate into the lungs. Through the branched surface of the bronchioles and alveoli, they are absorbed into the blood. Poisons that enter the blood through the respiratory system are distributed throughout the body, as a result of which their toxic effect can affect the most various organs and fabrics.

Harmful substances enter the digestive organs when swallowing toxic dusts deposited on the mucous membranes of the oral cavity, or by introducing them there with contaminated hands.

Poisons that enter the digestive tract along its entire length are absorbed through the mucous membranes into the blood. Absorption occurs mainly in the stomach and intestines. Poisons entering through the digestive organs are sent by blood to the liver, where some of them are retained and partially neutralized, because the liver is a barrier to substances entering through the digestive tract. Only after passing through this barrier do the poisons enter the general bloodstream and spread throughout the body.

Toxic substances that have the ability to dissolve or dissolve in fats and lipids can penetrate the skin when the latter is contaminated with these substances, and sometimes when they are present in the air (to a lesser extent). Toxins that penetrate the skin immediately enter the general bloodstream and are carried throughout the body.

Poisons that enter the body one way or another can be distributed relatively evenly throughout all organs and tissues, exerting a toxic effect on them. Some of them accumulate predominantly in certain tissues and organs: in the liver, bones, etc.

Such places of primary accumulation of toxic substances are called poison depot in organism. Many substances are characterized by certain types of tissues and organs where they are deposited.

The retention of poisons in the depot can be as follows: short-term, and more long-term- up to several days and weeks. Gradually leaving the depot into the general bloodstream, they can also have a certain, usually mild, toxic effect. Some unusual phenomena(alcohol intake, specific food, illness, injury, etc.) can cause faster removal of poisons from the depot, as a result of which their toxic effect is more pronounced.

Release of poisons from the body happens mainly through the kidneys and intestines; the most volatile substances are also released through lungs with exhaled air.

Emergency situations accompanied by the release of hazardous substances into the environment and their impact on people and the environment

Global production of chemical products, including hazardous chemicals, is constantly growing. All this increases potential danger occurrence of chemically hazardous accidents associated with the release or leakage of hazardous chemicals. According to statistics from the American company Dow Chemical, Lately In the United States, 17-18 emergencies involving hazardous chemicals occur every day. Moreover, they arise both during the production and use of hazardous chemicals, and during their storage and transportation.

The following can be cited as examples of emergencies associated with the release or leakage of hazardous chemicals.

In November 1979 There was a train crash in the province of Ontario (Canada), which contained tanks with chlorine, styrene, propane, toluene and other hazardous substances. The accident required the evacuation of more than 200 thousand people for 6 days.

In December 1984, at the Union Carbide chemical plant in Bhopal (India), which produces Sevin insecticides and Temik pesticide, an accident occurred with the release of about 43 tons of methyl isocyanate and its incomplete thermal decomposition products. The contamination zone with the ejection products was 5 km deep and more than 2 km wide. As a result of the accident, 3,150 people died, about 20 thousand people became completely disabled, and more than 200 thousand people suffered from various diseases from the consequences of poisoning.

March 20, 1989, Lithuanian SSR, city of Jonava - release of 7 thousand tons of ammonia into the atmosphere at a chemical plant producing mineral fertilizers. At the same time, a fire broke out in warehouses where 20 thousand tons of nitrophosphate fertilizers were stored. Wind direction from the city. 40 thousand people were evacuated, 6 people died. 64 people were defeated and undergoing treatment. According to scientists, it was a kind of “Chemical Chernobyl”, and if the wind had been on the city, it would have been a city of the dead.

In Nizhny Novgorod, on January 1, 1966 at 18.00, a spill of 27 tons of chlorine occurred at the Avtozavodsk water pumping station. Gas cloud at temperature t= -1°C and a wind speed of 1 m/s penetrated to a depth of 7 km in a residential area inhabited by 35 thousand people. Of these, about 20 thousand people did not smell chlorine and had no injuries (they were in residential multi-storey buildings on upper floors). Of the approximately 15 thousand people who were in the open area, they turned for help to medical institutions approximately 4 thousand people, a significant portion of whom were hospitalized for 3-5 days, 150 people were treated for a month.

From the above examples it is clear that accidents with the leakage of hazardous chemicals can lead to serious consequences.

Dangerous chemicals are found in large quantities at enterprises that produce or consume them.

It must be said that, as a rule, a small amount of toxic chemical products circulates in production lines. A significantly larger number of hazardous substances in terms of volume are kept in the warehouses of enterprises. This leads to the fact that in case of accidents in the workshops of enterprises, in most cases there is local contamination of the air, workshop equipment, and enterprise territories. Moreover, the defeat in such cases can mainly occur production personnel. In case of accidents at enterprise warehouses, when large-capacity containers are destroyed, hazardous chemicals spread outside the enterprise, leading to mass casualties not only of the enterprise personnel, but also of the population living near chemically hazardous enterprises.

On average, at enterprises the minimum (irreducible) reserves of chemical products are created for three days, and for plants producing mineral fertilizers for 10-15 days of work.

In addition, Federal Law No. 000 “On Industrial Safety” provides maximum quantities of chemically hazardous substances that can be stored and used in industrial enterprises:

Ammonia -500 t;

Ammonium nitrate - 2500 t;

Acrylonitrile - 200 t;

Chlorine - 25 t;

Ethylene oxide - 50 t;

Hydrogen cyanide - 20 t;

Hydrogen sulfide - 50 t;

Sulfur dioxide - 250 t;

Methyl isocyanate - 0.15 t.

At production sites or in vehicles, hazardous chemicals are usually contained in standard capacitive elements. These can be aluminum, steel and reinforced concrete shells, in which conditions are maintained that correspond to a given storage regime. Storage methods are selected depending on the physicochemical properties of hazardous substances. The main goal is to reduce the volume of stored substances, which is very important when using chemically hazardous substances on an industrial scale.

The main parameter influencing the choice of storage method is boiling point of hazardous substances.

The following main methods are used to store hazardous chemicals in enterprise warehouses:

• - in tanks under high pressure (in this case, the design pressure in the tank corresponds to the vapor pressure of the product above the liquid at the absolute maximum ambient temperature - chlorine, ammonia, etc.);
• - in isothermal storages at a pressure close to atmospheric (low-temperature storage) or up to 1 Pa (isothermal storage, in this case large-capacity spherical tanks from 900 to 2000 tons are used, for example, ammonia at t= -33.4°C);
• - storage at ambient temperature in closed containers (typical for high-boiling liquids - hydrazine, tetraethyl lead).

The method of storing hazardous chemicals largely determines their behavior during accidents.

Let's consider the development of an accident during storage of hazardous chemicals under pressure.

The nature of the development and the scale of the consequences of an incident at a chemical waste facility depends on the type, quantity and storage conditions of hazardous chemicals, on the characteristics of the facility and surrounding area, from the nature of the accident.

The most severe consequences are caused by the destruction of stationary and transport containers with hazardous chemicals.

The main feature when storing hazardous chemicals that have a boiling point below the ambient temperature and are located in a sealed container under pressure is that the substance in the container is relatively overheated normal conditions condition.

As a result, when the container depressurizes, that is, when the pressure drops to normal, the hazardous chemicals, being in an overheated state, begin to boil intensively, and extremely rapid evaporation of a certain part of the liquid occurs. This process only takes a few minutes. The resulting cloud of toxic chemical vapors and contaminated air is usually called primary cloud.

If the pressure in the container has dropped, but the main walls are intact (for example, cracks or a bullet hole), then the described process may be accompanied by an explosive, abrupt increase in pressure due to the increased volume of gas formed during evaporation, which will lead to additional destruction.

After completion of this process, the remaining liquid hazardous substance, being, as a rule, at atmospheric pressure, evaporates at a rate determined by the rate of heat supply to it. The resulting a cloud of contaminated air is called secondary.

The rate of evaporation of hazardous substances spilled from a damaged container depends on the influence of processes occurring during the interaction of hazardous substances with the underlying environment, significantly depends on the nature of the latter and changes over time.

Initially, rapid evaporation occurs as a result of heat transfer to the liquid from the underlying medium. As the underlying medium cools, its upper layer becomes an insulating layer and the flow of heat to the liquid from the underlying surface decreases and then practically stops. The evaporation process becomes stationary.

Most dangerous stage accidents, of course, are the first 10 minutes, when the evaporation of hazardous substances occurs intensively. In this case, during the first 2-3 minutes of the release of liquefied hazardous chemicals under pressure, an aerosol is formed in the form of heavy clouds, which, under the influence of their own gravity, fall to the ground.

At the first stage, the boundaries of the cloud are distinct, it has a high optical density and only after 2-3 minutes it becomes transparent. The temperature in the cloud is lower than in environment. Given its high density, the main factor determining the movement of the cloud in the accident area is gravity. At this stage, the formation and direction of movement of the cloud is uncertain. The radius of this zone can reach 0.5 - 1 km.

Subsequently, during a stationary evaporation process, a secondary cloud of contaminated air is transported in the direction of the average wind, forming a zone of chemical contamination.

On industrial facilities Usually a significant amount of flammable substances is concentrated, including hazardous chemicals (ammonia, ethylene oxide, carbon monoxide, etc.). In addition, many hazardous chemicals are explosive (hydrazine, nitrogen oxides, etc.). These circumstances should be taken into account when fires occur in enterprises. Moreover, the fire itself in enterprises can contribute to the release of various toxic substances. For example, when lump sulfur burns, sulfur dioxide is released in large quantities. The combustion of polyurethane and plastics leads to the release of hydrocyanic acid, phosgene, carbon monoxide, dioxin, and isocyanates in dangerous concentrations.

Therefore, when organizing work to eliminate a chemically hazardous accident at an enterprise and its consequences, it is necessary to evaluate not only the physicochemical and toxic properties of hazardous substances, but also their explosion and fire hazard, the possibility of the formation of new hazardous substances during a fire, and on this basis take the necessary protective measures personnel involved in the work.

Analysis of past emergency situations and calculations show that facilities with chemically hazardous components can be:

source of salvo emissions of hazardous chemicals into the atmosphere;

discharge of hazardous substances into water bodies;

“chemical” fire with the release of toxic substances into the environment;

destructive explosions;

contamination of objects and terrain at the source of the accident and on the trail of cloud spread;

extensive smoke zones in combination with toxic products.

As a result of accidents at chemical hazardous facilities, people and the environment may be exposed to contamination in areas of accidents, as well as in areas where aerosols and vapors of hazardous chemicals are distributed by air flows.

Contamination of food, food raw materials, fodder and water occurs due to the deposition of an aerosol of toxic chemicals or the sorption of their vapors from a cloud of contaminated air. Water sources can also be contaminated as a result of the ingress of toxic chemicals into them from contaminated areas with rain streams and groundwater or the direct flow of hazardous chemicals into them from destroyed (damaged) industrial and transport facilities. Humans and animals are affected by inhalation of contaminated air, contact with contaminated surfaces, consumption of contaminated food and fodder, and other ways.

The damaging effect of hazardous chemicals on people is determined by their ability, penetrating into the human body, to disrupt its normal activity, causing various painful phenomena, and under certain conditions, death.

The degree and nature of the normal functioning of the body (damage) depend on the characteristics of the toxic effect of hazardous chemicals, their physicochemical characteristics and state of aggregation, the concentration of vapors or aerosols in the air, the duration of their action, and the routes of penetration into the body.

Chemically dangerous objects and their classification

Such objects (COO) are considered chemically hazardous where chemically hazardous substances are produced, stored or used, and when destroyed, massive injuries to people, agricultural animals and plants from hazardous chemical substances (HAS) can occur.

COOs include enterprises of the chemical and petrochemical complex, refrigeration plants, meat processing plants, dairies, urban water treatment plants, gas, oil and ammonia pipelines, various storage agents and hazardous chemicals. The classification of chemical waste is based on a quantitative assessment of the degree of danger of the object, taking into account the following characteristics:

• - the scale of possible consequences of a chemical accident for the population and areas adjacent to the facility;
• - type of possible emergency in case of an accident at a chemical facility according to the worst scenario;
• - the degree of danger of hazardous chemicals used at chemical waste facilities;
• - the risk of an accident at the chemical facility.

Based on the scale of the possible consequences of a chemical accident, chemical waste products are divided into four degrees of chemical hazard.

CW hazard indicator based on the possible scale of consequences of the accident:

Chemically hazardous facilities of the 1st degree include large chemical industry enterprises and water treatment facilities located in close proximity to or on the territory of major cities.

Objects of the 2nd degree of chemical waste include enterprises of the chemical, petrochemical, food and processing industries, water treatment facilities for public utilities in large and medium-sized cities, and large railway junctions.

Objects of the 3rd degree of chemical waste include small enterprises of the food and processing industry (refrigeration plants, meat processing plants, dairies, etc.) of local importance, water treatment plants, etc. in medium and small cities and rural settlements.

4th degree chemical waste facilities include enterprises and facilities with a relatively small amount of hazardous chemicals (less than 0.1t).

The data presented allow us to draw the following conclusions:

• - the danger of contamination with hazardous chemicals really exists;
• - it is necessary to predict and assess the chemical situation in advance;
• - it is necessary to train the entire population on methods of protection from hazardous substances and the rules of behavior of people in emergency situations.

Rules of conduct and actions of the population in case of accidents with hazardous substances and hazardous substances

A distinctive feature of emergencies arising from accidents at chemically hazardous facilities is that with high concentrations of hazardous chemicals or chemical agents, people can be affected in a short time.

Accidents at chemically hazardous facilities can be accompanied by destruction, fires and explosions, which increases the radius of the accident area by 1.5 - 2 times, which is justified by the possibility of release of a large number of hazardous substances under these conditions due to an explosion.

As a result of an accident at the HOO service staff and the population living near the facility may be seriously injured by toxic substances. Chemical toxicants have a damaging effect on people when their vapors enter the atmosphere, when these substances spill on the ground and on various surfaces with which people come into contact.

The main measures to protect the personnel of the chemical facility and the population in case of accidents (destructions) are:

• - use of personal protective equipment and shelters (in filter ventilation or isolation mode);
• - use of antidotes and skin treatments;
• - compliance with behavior (protection) regimes in the contaminated area;
• - evacuation of people from the contaminated zone resulting from the accident;
• - sanitary treatment of people, decontamination of clothing, territory, transport, equipment and property.

Personnel and the public working at chemical waste facilities and living near them must know the properties features and the potential danger of hazardous chemicals used on this object, ways personal protection from damage to hazardous substances, be able to act in the event of an accident, provide first aid to those affected.

Workers and employees, upon hearing a chemical hazard warning signal, must immediately put on personal protective equipment (gas masks or self-contained gas masks).

Everyone at their workplace must ensure the correct shutdown of energy sources, stop units, devices, and shut off gas, steam and water communications.

Then the personnel take refuge in prepared shelters or leave the affected area. When a decision to evacuate is announced, workers and employees are required to immediately arrive at the prefabricated evacuation points of the facility.

Workers belonging to non-military civil defense formations, upon receiving a signal about an accident, arrive at the assembly point of the formations and participate in the localization and elimination of outbreaks chemical damage.

The population living near chemical hazardous substances, in case of accidents with the release of hazardous substances, having heard the warning signal on the radio (television) must put on gas masks, close windows and vents, turn off electric heating and Appliances, gas, dress the children, take the necessary warm clothes and food (3-day supply of non-perishable food), warn neighbors, quickly leave the residential area in the indicated direction or to the side, perpendicular to the direction wind, preferably on an elevated, well-ventilated area, at a distance of at least 1.5 km from previous place stay, where to remain until further instructions are received.

If you do not have a gas mask, you must quickly exit the infected area, holding your breath for a few seconds. To protect the respiratory system, you can use improvised items made from fabrics soaked in water, fur and cotton parts of clothing. When they close the respiratory organs, the amount of inhaled gas decreases, and, consequently, the severity of the damage.

When driving in contaminated areas, the following rules must be strictly observed:

• - move quickly, but do not run and try not to raise dust;
• - do not lean against buildings or touch surrounding objects;
• - do not step on drops of liquid or powdery deposits of unknown substances encountered along the way;
• - do not remove personal protective equipment until instructed;
• - if drops of hazardous substances are found on the skin, clothing, shoes, personal protective equipment, remove them with a paper swab, rag or handkerchief;
• - provide the necessary assistance to the injured, the elderly, and those unable to move independently.

After leaving the infected area, you need to undergo sanitary treatment. Those who have received minor injuries (cough, nausea, etc.) go to medical institutions.

About eliminating the danger of chemical damage and about the procedure further actions the population is notified by civil defense headquarters or police authorities.

Measures to protect the population and territories carried out in advance

Engineering activities

• 1. Design and construction of chemical facilities taking into account the danger of exposure to natural emergencies, outside areas of mass residential development, on the leeward side in relation to them.
• 2. The placement of hazardous chemicals tanks on the territory of the facility is dispersed in groups. Providing reserve tanks for pumping hazardous chemicals from faulty ones.
• 3. Use of safe technologies, implementation of organizational, technical special and other measures to ensure high operational reliability of hazardous chemicals, as well as limiting the spread of hazardous chemicals outside the sanitary protection zone in the event of accidents and destruction.
• 4. Increasing the level of automation and mechanization technological processes, equipped with high-speed technical means protection, including automatic shut-off devices, explosion prevention systems and accident localization, as well as improvement vocational training personnel.
• 5. Reducing stocks of hazardous chemicals to the minimum quantities required by technology. This is especially important at the stages of loading and unloading operations in storage facilities for raw materials and finished products.
• 6. Ensuring high reliability of energy and water supply, introducing a system for accident-free shutdown of production in the event of sudden interruptions in the supply of energy and water.
• 7. Construction for the personnel of the chemical facility and the population living in danger zone, funds collective defense with filtering and ventilation equipment.

Organizational events

• 1. Planning for the protection of chemical equipment personnel and the population during accidents, carried out in accordance with general provisions planning for this species Emergency.
• 2. Creation and maintenance of constant readiness forces and means to eliminate the accident:
  • - Forces - regular formations of the chemical weapons organization, formations of the RSChS of various levels depending on the scale of the accident, including half-division chemical protection.
  • - Means - devices and systems for monitoring the chemical situation; fire-fighting equipment; engineering equipment: bulldozers, scrapers, excavators, etc.; means of neutralizing hazardous chemicals at this chemical waste facility; means of eliminating accidents on energy networks; special protective equipment, insulating and industrial gas masks, other means of protection against hazardous chemicals.
• 3. Providing personnel of the chemical facility and the population (primarily in a 1.5-2 kilometer zone from the chemical facility) with personal respiratory protection equipment:
  • - PPE for chemical plant personnel - insulating industrial gas masks and protective clothing according to the type of hazardous chemicals at this facility.
  • - PPE for the population - civilian gas masks, if necessary with additional cartridges with protection against a specific type of hazardous chemicals.
• 4. Control of the chemical situation using stationary, mobile and personal devices and chemical control systems.
• 5. Creation of an operational local warning system within a 1.5-2 kilometer zone directly by the control service of the chemical enterprise.
• 6. Preparation of chemical plant personnel and the public for actions in emergency conditions. Particular attention is paid to training the population living in the most dangerous 1.5-2 kilometer zone around hazardous chemicals, protection from specific hazardous chemicals.

Measures to protect the population and territories taken in the event of an accident at a chemical facility

• 1. Assessment of the actual chemical situation in the area of ​​the accident from instruments and systems for monitoring the chemical situation, forecasting its development.
• 2. Determination of decisions on measures to protect the population from an accident

The main way to protect the population during accidents at chemical weapons equipment is to take shelter in protective structures and in sealed rooms with the simultaneous use of personal protective equipment, including protozoa. In addition, protective measures may be taken such as the use of various personal protective equipment; if possible, independent exit of the population from the contaminated zone; medical assistance to victims; sanitary treatment of people; degassing of territory, transport, equipment and property; restriction of public access to the accident area.

Evacuation of the population, given the rapidity of the accident, will have serious difficulties in carrying out, especially related to the possibility of panic among the population, and therefore is an extreme protective measure and is carried out in exceptional cases. The most effective emergency evacuation of the population can be carried out before the arrival of the primary cloud of hazardous substances.

To limit public access to the accident area, checkpoints are organized, cordoning off the contaminated area, setting up posts and installing barriers on roads leading to the contamination zone, patrolling the streets of cities and towns, regulating traffic on evacuation routes, installing warning signs (boards) at the borders of pollution zones.

3. Notifying the personnel of the chemical facility and the public about the accident

Notification of the personnel of the chemical facility and the population within a 1.5-2 km zone is carried out by the dispatch service of the chemical facility, and the rest of the population - by civil defense and emergency management bodies at various levels.

The alert is transmitted to all enterprises and settlements, "located within an area limited by a radius equal to the maximum possible depth of spread of hazardous chemicals under given meteorological conditions. After receiving a signal about a chemically dangerous accident, personal and collective protective equipment is prepared for use, and in some cases, preparatory measures for an emergency can be carried out evacuation of personnel and the population. Upon an alarm signal in all rooms, ventilation systems without filters are switched off or switched to internal circulation mode, and with filters they are switched on to filter ventilation mode.

The warning system uses electric sirens and equipment remote control and circulation call. In addition, television and radio broadcasting, industrial public address equipment and telephone communications can be used for notification.

Considering the possibility of receiving a large number of requests from various organizations and the population in the event of the occurrence of chemically dangerous accidents and notification of them, it is advisable to organize an information (reference) service at the hazardous waste facility, which, as the accident progresses and during the liquidation of its consequences, should provide information, especially on the rules of behavior of people in conditions of contamination with hazardous chemicals.

Elimination of accidents

When eliminating accidents, rescue and other urgent work, taking into account the specifics of this emergency, and the localization of the accident.

Emergency rescue operations include:

monitoring the implementation of the required protection measures by the population;

detecting victims, removing them from the contaminated area, providing first aid medical care and, if possible, emergency evacuation to safe areas;

sanitary treatment of people;

purification of food and water, degassing of transport, structures and terrain.

Other urgent work carried out in the interests of rescue work usually include:

degassing transport routes in contaminated areas;

localization of accidents on utility networks;

extinguishing fires.

When localizing accidents priority are work related to limiting the spread of the liquid phase of hazardous chemicals and reducing the rate of its evaporation.

To limit the release of the liquid phase of hazardous chemicals from the container, measures are taken to eliminate the leak, if possible, or to pump liquid from the emergency container to the spare one.

Such work should be carried out under the guidance and with the direct participation of specialists from the industry that produces and transports these harmful substances. Pumping is carried out by methods and means accepted in industry.

Limiting the spread of hazardous substances on the ground in order to reduce the evaporation area is carried out using engineering means(bulldozers, scrapers, excavators, etc.) It consists of creating obstacles in the form of shafts of moved or poured soil. It is also possible to direct flows of the liquid phase of hazardous chemicals into natural depressions. When carrying out work, it is necessary, first of all, to prevent the entry of hazardous chemicals into rivers, lakes, underground communications, basements of buildings, structures, etc.

IN in some cases the liquid phase can be collected in special containers for subsequent neutralization.

Reducing the rate of evaporation of hazardous chemicals can be done in several ways:

absorption of the liquid phase of hazardous chemicals by a layer of bulk adsorption materials (soil, sand, slag, etc.);

isolation of the liquid phase of hazardous chemicals with foams;

diluting liquid hazardous substances with water or solutions of neutralizing substances.

To absorb the liquid phase of hazardous substances with a layer of bulk adsorbents, the material is scattered (pushed) onto the liquid phase. In this case, the thickness of the adsorbent layer must be at least 10-15 cm. Contaminated bulk materials and the top layer of soil (to the depth of absorption of hazardous substances) are, if necessary, collected in special containers for subsequent removal to neutralization sites.

In cases where environmental protection conditions allow neutralization of hazardous substances on site, contaminated adsorbent and soil are not collected or removed. If hazardous substances are capable of burning and environmental conditions allow, then small contaminated areas can be burned out.

Isolation of the liquid phase of hazardous chemicals with foams is carried out in order to reduce the release of vapors into the atmosphere. To do this, neutralizing additives can be introduced into the foam, which enter into chemical interactions with hazardous chemicals, resulting in the formation of non-toxic or low-toxic substances.

The main and most accessible way to reduce the rate of evaporation of hazardous chemicals is dilution of the liquid phase with a stream of water or solutions of neutralizing substances. Water or solutions of neutralizing substances can be supplied to the source of the accident in finely dispersed form or in compact jets. The finely dispersed fraction in the form of an “umbrella” ensures the neutralization and elimination of spraying of toxic chemical vapors. The compact jet is used to neutralize concentrated acids, oxidizing agents and other substances that react violently with water.

Localization and then liquidation of chemically hazardous accidents is organized by emergency commissions.

To eliminate chemically hazardous accidents, the CoES uses special rescue teams, regular and non-regular detachments and teams of economic and social facilities, as well as territorial non-regular formations of the RSChS.

Elimination of a local accident at a chemical facility is carried out special regular gas rescue teams and emergency formations of the facilities themselves.

In addition to the forces and means of the enterprise, units and formations of the city (district, region) may be involved in the liquidation of a local accident. Management of the liquidation of a local accident is carried out by operational groups for carrying out emergency work enterprises or the relevant emergency commission.

In addition to the forces and means of the enterprise and the RSChS, military units and units may be involved in the liquidation of a territorial accident.

The management of the work to eliminate such an accident is carried out, depending on the scale, by the regional (territorial) or republican CoES, and in the case of particularly severe consequences of the accident - by the Interdepartmental Commission for Emergency Situations.

When chemically hazardous transport accident during transportation of hazardous substances the organization of its liquidation also depends on the scale of the accident and its consequences.

Minor accidents (violation of the tightness of locking devices, etc.) are corrected by specialists accompanying vehicles with hazardous substances. In case of larger accidents associated with a violation of the tightness of the tank, with a significant release (leakage) of hazardous substances, the elimination of accidents and its consequences is organized by the railway department with the participation of local emergency response teams. If the accident occurred during the transportation of hazardous substances by car, then the liquidation is carried out by the district (city or regional) CoES. Special teams from shipper enterprises, as well as units (divisions) may also be involved in the elimination of such chemical accidents and their consequences. civil defense.

The effect of toxic exposure depends on the amount of hazardous substances entering the body, its physicochemical properties, duration and intensity of intake, interaction with biological media (blood, enzymes). In addition, the effect depends on gender, age, individual sensitivity, routes of entry and exit, distribution in the body, as well as meteorological environmental conditions.

Along with general hazardous chemicals, they have selective toxicity, i.e. they pose the greatest danger to a specific organ or system of the body. According to selective toxicity there are:

· cardiac with a predominant cardiotoxic effect (many medications, plant poisons, metal salts - barium, potassium, cobalt, cadmium);

· nervous, causing disturbances in mental activity (carbon monoxide, organophosphorus compounds, alcohol and its surrogates, drugs, sleeping pills);

hepatic (chlorinated hydrocarbons, poisonous mushrooms, phenols and aldehydes);

· renal (heavy metal compounds, ethylene glycol, oxalic acid);

· blood (aniline and its derivatives, nitrites, arsenous hydrogen);

· pulmonary (nitrogen oxides, ozone, phosgene).

Toxic effect upon exposure different doses and concentrations of hazardous substances may manifest themselves as functional and structural (pathomorphological) changes, i.e. toxicity manifests itself in the form of threshold doses and concentrations. But the result may be the death of the organism in the case of lethal concentrations.

Lethal (lethal) doses of DL when administered to the body (or lethal concentrations of CL) can cause isolated cases of death or death of all organisms. Average lethal doses and concentrations (DL50, CL50) are used as toxicity indicators. The average lethal concentration of a substance in the air is the concentration of a substance that causes the death of 50% of experimental animals after 2-4 hours of inhalation exposure (mg/m³). The average lethal dose when administered into the stomach (mg/kg) is designated as DL50g, when applied to the skin - DL50k.

The danger of poisons can also be judged by the threshold values harmful effects(one-time, chronic) and threshold of specific action).

The threshold of harmful action is the minimum concentration (dose) of a substance, upon exposure to which changes in biological indicators at the organismal level occur in the body, going beyond the limits of adaptive reactions, or hidden (temporarily compensated) pathology.

The nature of the impact of harmful substances on the body and General requirements safety are regulated by GOST 12.0.003 - 74, which divides substances into:

· toxic, causing poisoning of the whole body or affecting individual systems (central nervous system, hematopoiesis), causing pathological changes in the liver and kidneys;

· irritating, causing irritation of the mucous membranes of the respiratory tract, eyes, lungs, skin;

· sensitizing, acting as allergens (formaldehyde, solvents, varnishes based on nitro- and nitroso compounds);

· mutagenic, leading to disruption of the genetic code, changes in hereditary information (lead, manganese, radioactive isotopes);

· carcinogenic, causing malignant neoplasms (cyclic amines, aromatic hydrocarbons, chromium, nickel, asbestos);

· affecting reproductive (childbearing) function (mercury, lead, styrene, radioactive isotopes).

The danger of hazardous chemicals in contaminating the surface layer of the atmosphere is determined by their physicochemical properties, as well as their ability to enter a damaging state, that is, to create a damaging concentration or reduce the oxygen content in the air below the permissible level. All hazardous chemicals can be divided into three groups, based on boiling point at atmospheric pressure, critical temperature and ambient temperature; aggregate state of hazardous substances; storage temperature and operating pressure in the container.

The 1st group of hazardous substances has a boiling point below -40°C. When released, only a primary gas cloud is formed with the likelihood of an explosion and fire (hydrogen, methane, carbon monoxide), and the oxygen content in the air (liquid nitrogen) also sharply decreases. When a single container is destroyed, the duration of the gas cloud does not exceed 1 minute.

The 2nd group of hazardous substances has a temperature higher than the ambient temperature. To bring such hazardous substances into a liquid state, they must be compressed and stored refrigerated (or under pressure at normal temperature) - chlorine, ammonia, ethylene oxide. The release of such hazardous substances usually produces a primary and secondary cloud of contaminated air (CAC). The nature of contamination depends on the relationship between the boiling points of hazardous substances and air temperature. Thus, butane (boiling point - 0 °C) in hot weather will be similar in action to hazardous chemicals of the 1st group, i.e. Only the primary cloud will appear, and in cold weather - the 3rd group. But if the boiling point is lower than the air temperature, then when the container is destroyed and hazardous substances are released, a significant part of it may end up in the primary pollutant. In this case, significant air hypothermia and moisture condensation may be observed at the accident site.

The 3rd group of hazardous substances is characterized by a boiling point above 40°C, i.e. all hazardous substances that are in a liquid state at atmospheric pressure. When they spill, the area becomes contaminated with the risk of subsequent contamination of groundwater. It takes a long time for liquid to evaporate from the soil surface, i.e. the formation of a secondary cloud of pollutants is possible, which expands the affected area. The most dangerous hazardous substances (ADV) of the 3rd group are if they are stored in elevated temperature and pressure (benzene, toluene).

Many of us have encountered dangerous and toxic substances in our lives, and some could even die due to the fumes that come from them. This may be due to the specifics of work at some enterprises. But in order to protect yourself and your family from danger, you need to know exactly what substances that are dangerous from a chemical point of view are and how to protect yourself from them.

AKHOV: what is this?

An emergency chemically hazardous substance (HAS) is a dangerous chemical compound that is used in industry or agriculture; when released into the air or onto the soil, contamination can occur, and as a result, begins to affect Negative influence on all living organisms.

An OHV is a compound that can, through direct or indirect effects on the body, cause damage or even death.

Today, hazardous substances are produced in large quantities throughout the world, in Russian Federation Rescuers often encounter the most common connections. Dangerous hazardous substances can be in different states of aggregation.

Properties of hazardous substances

Hazardous substances have several basic properties: density, toxicity, solubility, volatility, viscosity, chemical properties and boiling point.

Density is the mass of a substance per unit volume. This indicator has a direct impact on the spread of toxic substances in the atmosphere and in the area. If substances are in the form of gas or vapor, then they are heavier than air, their concentration at the surface of the earth will be maximum and decrease with height. which have a density higher than that of water, after entering a body of water they end up at the bottom.

Solubility is another characteristic of hazardous chemicals; it means the ability to form solutions with other components. Toxic components are highly soluble in water; they can contaminate bodies of water so strongly that they will be unsuitable not only for use by people and animals, but also for technical purposes. In addition, such substances can also contaminate the soil, and to a fairly large depth.

This ability of hazardous substances ensures their rapid spread throughout all internal organs human body. In order to eliminate all hazardous components from water bodies, it is necessary to use solutions of degassing substances, and in order to eliminate poorly soluble compounds from water, it is necessary to use special disinfectants.

Volatility is the ability of a substance to pass into the vapor state. Highly volatile toxic substances at high temperatures have the ability to degas naturally. But volatility directly depends on what the boiling point is at atmospheric pressure and the vapor concentration.

Viscosity is, in liquid form, resistance to the movement of some parts of the liquid relative to others. In addition, the absorption of the substance into materials with a porous structure depends on this parameter.

Classification of chemical substances

The classification of chemically hazardous substances is one of the most important points, thanks to which in the future you can quickly react and provide assistance to everyone who is in the contaminated zone. Hazardous substances according to the degree of impact on humans can be divided into four classes:

• extremely dangerous;
• dangerous;
• moderately dangerous;
• low-risk.

But in terms of their damaging qualities, all dangerous substances are heterogeneous. The main damaging effect is most often the sign of the predominant syndrome, which occurs during an acute form of intoxication of the human body. Following this, a chemically hazardous substance may belong to one of these groups:

• asphyxiants (chlorine, phosgene and others);
• general poisonous;
• asphyxiating and generally toxic (nitrogen oxides, nitric acid, sulfur dioxide);
• asphyxiating and neurotropic (ammonia);
• poisons that affect metabolic processes in the body (ethylene oxide).

Characteristic

Characteristics of hazardous substances according to physical properties defined by the following groups:

Where should hazardous substances be stored and in what form?

To prevent an involuntary release of chemically hazardous substances, you must strictly follow safety precautions when working with them, and be sure to store them only in special containers and rooms.

Dangerous chemicals are found in large quantities in enterprises that produce or consume them. In chemical plants they can be used as initial, intermediate, by-product or final raw materials. Their reserves are placed in special storage facilities (up to 80%), they can be located in equipment, vehicles, such as pipelines, tanks and others. The most common hazardous chemicals are liquefied ammonia and chlorine. Some enterprises store tens of tons of hazardous substances, and transport the same amount by rail or pipelines.

All hazardous substances can be divided into:

Dangerous substances include substances that pose a serious danger only in situations where accidents occur.

Types of hazardous chemicals

To date, a list of hazardous substances has not been developed, but there is a small list of substances that are often used in enterprises and if they are not stored under the right conditions, a chemical accident may occur. Today we can distinguish 9 main substances that pose an extreme danger to humans and the environment, among them most often chlorine, ammonia, hydrogen sulfide, carbon disulfide, and hydrogen fluoride.

Impact of hazardous substances on humans

A chemical accident can lead to the release of substances hazardous and toxic to humans into both the air and water. All hazardous components can have different effects on the human body and have different effects:

How to determine accidents with the release of hazardous substances yourself and is it possible to do this?

Signs of chemical contamination

A person himself can determine the release of chemical substances on his own. There are a number of signs that should force you to take appropriate protective measures, or rather:

• the appearance of a cloud that gradually grows and has an unnatural origin;
• not very pleasant odors, including those that cause a feeling of suffocation;
• loss of consciousness in people and general malaise;
• panic state;
• rapid withering of trees and other vegetation, death of animals and birds.

Protection rules

All of the above-described signs of an accident with the release of hazardous chemicals should force a person not only to report the disaster that has occurred, but also to independently take protective measures:

Dangerous enterprises

An emergency chemically hazardous substance can most often be found at an enterprise where it is used in production or, conversely, is produced. Such enterprises include:

• chemical, oil refining, petrochemical and other organizations working in the same direction;
• enterprises on the territory of which refrigeration units are installed, and they use refrigerant - ammonia;
• treatment plants that use chlorine.

All enterprises classified as hazardous are called a chemically hazardous facility (CHF), on the territory of which hazardous substances are stored, processed, transported or used. At such enterprises, an emergency chemically hazardous substance, if stored incorrectly, can lead to emergency situation. Therefore, every employee must undergo safety procedures and know exactly what to do if a harmful substance suddenly leaks.

Protecting the public from chemicals

Chemical substances and hazardous objects pose a serious threat not only to the environment, but also to humans, so in this case it is necessary to take chemical protection that will help eliminate or reduce their impact on the population and personnel of the enterprise, and reduce the scale of the consequences of the accident.

All measures related to chemical protection must be carried out in advance, and not at a time when an accident has already occurred. Measures are taken with all employees of a hazardous enterprise and residents of nearby areas that can protect them from exposure to hazardous chemicals:

• systems are created and subsequently used to monitor the chemical situation in hazardous areas;
• warning systems are installed;
• plans are being developed to eliminate the chemical accident;
• protective equipment is purchased in sufficient quantities and stored in full readiness;
• special shelters are maintained in readiness, where chemicals and dangerous objects do not penetrate. Must monitor their readiness to receive people in the event of an accident;
• all measures are taken to protect food, food raw materials, and water;
• readiness is ensured RSChS forces to eliminate the consequences of chemical accidents.

If suddenly an accident occurs and there are victims, then in this case everyone who works in a dangerous enterprise must be able to provide first aid.

First aid for poisoning with hazardous chemicals

It is possible to provide effective assistance in case of damage to hazardous chemicals only if the characteristics of chemically hazardous substances are immediately known. Correctly determining what poisoned the victim’s body with, will help you quickly respond and provide first aid, which most often consists of the following measures:

Conclusion

As it became clear from the article, there are many dangerous substances in the world and it is impossible to do without them, but only precautionary measures and compliance with safety precautions will avoid accidents. If, nevertheless, this failed, then in this case it is possible to save the lives of people and animals only thanks to quick response and use of all existing protection measures.

Nowadays, more than six million different chemical compounds are known that people regularly encounter in their lives. Everyday life. They are often used in everyday life, industrial and agricultural industries, but some of them are very dangerous and toxic. These highly toxic substances, in the event of large emissions or spills, can lead to massive injury to people and all living organisms, and can also cause contamination of the environment, water and soil, which is why they are also called hazardous substances.

Description

Mainly in factories specializing in the defense, pulp and paper, metallurgical and oil industries, a large number of stocks of hazardous substances. The decoding of this abbreviation sounds like “emergency chemically hazardous substances,” since the release of such compounds into the air will lead to poisoning and death of a huge number of people. In the event of a disaster at the enterprise where they are stored, all living things will be affected not only directly at this facility, but also far beyond its borders.

The most common emergency chemically hazardous substances that are included in the list compiled and approved by the headquarters of the Civil Defense of the Russian Federation are ammonia, liquefied chlorine, sulfur dioxide, nitrile, hydrocyanic and acrylic acids, benzene, fluorine and hydrogen bromide. Some enterprises contain tens of thousands of tons of them. Typically these substances are stored in a gas or liquid state. They are transported around the clock using rail and pipeline transport. Some of them are the most harmful to humans and in the event of an accident, moving in the direction of the wind, they can be transported over vast distances.

Characteristics of especially dangerous hazardous substances

The following potent toxic substances are considered the most harmful:

• NH 3 (ammonia) is a colorless gas with the odor of ammonia. It is mainly used for the production of liquid fertilizers and nitrate, as well as soda. Besides this substance can also be used for dyeing fabrics and silvering mirrors. It irritates mainly the respiratory tract, as well as mucous membranes and skin.
• Cl 2 (chlorine) has the appearance of a yellowish gas with a pronounced pungent odor. When evaporating it always forms a mist white with water vapor. This hazardous chemical substance is used for water treatment and is widely used in the textile industry. This gas greatly irritates the human respiratory tract and can even cause pulmonary edema.
• HCN (hydrogen cyanide, or hydrocyanic acid) is a colorless liquid with a bitter almond odor. It is often used in the production of plastics, organic glass and artificial fiber. This substance blocks intracellular enzymes that contain iron, and thus causes suffocation of all human tissues.
• SO 2 (sulfur dioxide) is a colorless gas with a pungent odor and a sweetish taste. This hazardous chemical substance, when coming into contact with water, can form sulfurous acid. It is often used as a bleach or in the food industry as a preservative. This gas affects the respiratory tract and can cause clouding of the cornea of ​​the eye.
• H 2 S (hydrogen sulfide) is a third-party product obtained during the processing of various petroleum products, as well as during the coking of coal. This gas is colorless and has a rotten egg odor. It is also used in the production of sulfur. It mainly affects the lungs, and poisoning with it can lead to their swelling.
• CO (carbon monoxide) is a colorless and odorless gas. When ignited, it appears as a blue flame. Poisoning with this substance is called intoxication.
• C 4 H 4 O 2 (dioxin) is a compound containing two benzene rings in which two hydrogen atoms are replaced by chlorine. This powerful poison is produced at enterprises where fuel is produced, as well as at pulp and paper mills and electrolysis plants. Poisoning with it leads mainly to death.
• C 6 H 6 (benzene) has the form of a colorless liquid with a pungent odor. It is formed as a result of coal coking. It is used most often for the synthesis of pesticides, as well as in the production of many pharmaceuticals and as a solvent for various fats and varnishes. Poisoning with this substance can lead to loss of consciousness and convulsions.

Classification by method of penetration and degree of danger

All of the above chemical substances are further divided into groups depending on how certain hazardous substances enter the body. Classifying them into in this case looks like this:

• Penetrating through the respiratory tract.
• Poisons that enter the human body through the gastrointestinal tract, that is, through the mouth.
• Substances that have a toxic effect through the skin.

In addition, there is a classification of hazardous substances by hazard class, which looks like this:

• Extremely harmful, potent poisons, leading mainly to death when poisoned by them. These include hydrocyanic acid, chemical compounds mercury, lead, zinc and cadmium, as well as nitrites, phosgene, ethylene oxides and hydrogen chloride.
• Highly dangerous are various acids of organic origin, ammonia, compounds containing sulfur, phenols, cresols, as well as all kinds of acidic aldehydes.
• All other chemical compounds are usually classified as moderately harmful and low-hazard hazardous substances. Decoding them in this case also sounds like “emergency chemically hazardous substances,” but poisoning with them cannot lead to such dire consequences, unlike the two previous classes.

Classification by physical properties

All hazardous substances are also divided into groups according to the nature of their behavior on the ground, in the air and in the water. Their classification in this case depends on their most important parameter, thanks to which it is determined how a particular substance will behave when released or spilled into the atmosphere, that is, what will be the maximum concentration of its vapors in the air.

In industrial toxicology, they also use such an indicator, with which one can immediately take into account the toxicity and volatility of a chemical substance.

Classification by storage method

Due to different physical and chemical properties, hazardous chemicals must be located in completely different conditions at enterprises. Their classification in this case is as follows:

• The first category is substances that have a low critical temperature and are stored in a compressed state (nitrogen oxide, natural gas).
• The second group is hazardous chemicals that are in a liquefied state and boil at low degrees (sulfur dioxide, chlorine, ammonia and others).
• The third category is liquid substances, stored at normal atmospheric pressure. Most of the hazardous substances belong specifically to this group.
• The fourth type - stored in solid form and can cause great harm in fires (dioxin, salts heavy metals and others).

Accidents with the release of hazardous chemicals of the first and second categories are especially dangerous, since when these substances enter the atmosphere, they quickly boil with instant evaporation.

Emergencies

Depending on the affected area, all disasters, in turn, are divided into private, local, object, regional and global in nature. The release of hazardous substances can occur as a result of the destruction of tanks, pipelines or reservoirs, as well as due to equipment breakdown, transport accidents and various natural disasters.

Such disasters can lead to the death of people, animals, plants, as well as contamination of food, feed and the atmosphere. The media should notify the population about the occurrence of such an emergency, and also give recommendations on how to behave in the contaminated zone. But if this does not happen, you can recognize the approach of a disaster yourself, and it is imperative to know all the precautions to survive and maintain your health.

Signs of danger

If there is a release or spill of hazardous substances, an accident cannot be avoided. It can be detected by the following signs:

• An expanding cloud appears, the origin of which is unnatural.
• Your health deteriorates sharply.
• There is an instant wilting of plants and all greenery.
• Nauseous and suffocating odors appear.

It is also possible to recognize which emission toxic substance occurred due to symptoms of poisoning.

Classification according to the nature of the impact on humans

Chemical toxicants have completely different effects on people. Their classification in this case looks like this:

• Asphyxiating poisons (chlorine, phosphorus oxychloride and others). When they enter the body, they begin sharp pains in the chest, clouding and burning in the eyes, severe cough, dry mouth, nausea, and impaired coordination of movements.
• Generally toxic hazardous substances (cyanchloride, carbon monoxide, etc.). Poisoning with these substances instantly causes convulsions, loss of consciousness occurs, respiratory paralysis may occur, as well as severe burning in the respiratory tract.
• Neurotropic substances (phosphorus compounds, carbon disulfide). They influence generation and behavior.
• Poisons of asphyxiating-neutropic action (ammonia) - when poisoned with these hazardous substances, a cough and runny nose appears, it becomes difficult to breathe, dizziness, heart rate increases, and redness and itching of the skin occurs.
• Metabolic substances (dioxin, ethylene oxide, etc.). Poisoning with these poisons most often causes organ mutations or leads to death.

Security measures

To protect yourself from such terrible consequences of poisoning, you need to know how to behave if danger arises in the event of a release of hazardous chemicals:

• If there is a shelter somewhere nearby, then you need to immediately take refuge in it.
• Put it on urgently gauze bandage and protect your skin from damage with thick clothing.
• While at home, it is necessary to tightly close all windows, as well as doors and ventilation.
• To protect the respiratory system, you can also use a towel soaked in a saline or soda solution.

Means of protection against hazardous chemicals

The most reliable protection against these poisons are gas masks and respirators. They can protect a person from the vapors of these substances if they are in good working order and correspond to their height.

The gas mask should fit tightly to the face and not cause any pain in the person. When purchasing these protective equipment, you need to know the size of your head from crown to chin.

Helpful information

Also, do not forget about precautions in your home to protect yourself and your loved ones from chemical poisoning:

• All chemicals, including household chemicals, should be kept out of the reach of children and kept separate from food and water.
• Do not store unknown or unnecessary chemicals in the apartment.
• When using detergents, it is better to wear gloves and an apron.

Thus, properly organized protection against hazardous chemicals is an important factor in saving people and all living organisms in the event of an emergency.

Accidents at chemically hazardous facilities occupy one of the most important places. The chemicalization of the industrial industry in the second half of the twentieth century led to an increase in man-made hazards associated with chemical accidents, which can be accompanied by emissions of hazardous chemical substances (HAS) into the atmosphere, significant material damage and large casualties. According to statistics, in recent years, in the Russian Federation, 80-100 accidents annually occur at chemically hazardous facilities with the release of hazardous chemicals into the environment.

Chemically hazardous object(HOO) is a facility where hazardous chemicals are stored, processed, used or transported, in the event of an accident or destruction of which, death or chemical contamination of people, farm animals and plants, as well as chemical contamination of the natural environment, may occur.

COOs include enterprises chemical, oil refining, petrochemical and other related industries; enterprises with industrial refrigeration units that use ammonia as a refrigerant; water supply and treatment plants that use chlorine and other enterprises. Classifying such enterprises as dangerous production facilities produced in accordance with the criteria for their toxicity established federal law“On industrial safety of hazardous production facilities.” There are four categories of CW danger level: I - when more than 75 thousand people fall into the zone of possible chemical contamination, II - from 40 to 75 thousand people, III - less than 40 thousand people, IV - zone of possible chemical contamination that does not extend beyond limits of the territory of the facility or its sanitary protection zone. Currently, there are more than 3,600 chemical plants operating in the country. dangerous objects, 148 cities are located in areas of high chemical hazard. The total area where a source of chemical contamination may occur is 300 thousand km2 with a population of about 54 million people. In these conditions, knowledge of the damaging properties of hazardous chemicals, advance prediction and assessment of the consequences of possible accidents with their release, the ability to act correctly in such conditions and eliminate the consequences of emergency releases is one of the necessary conditions for ensuring the safety of the population.

For the needs of emergency rescue, the concept of “emergency chemically hazardous substance” is used, which is a dangerous chemical substance used in industry and agriculture, in the event of an emergency release (spill) of which the environment can be contaminated in concentrations that can affect a living organism (toxodoses). The most important property of hazardous chemicals is toxicity, which means their toxicity, characterized by lethal, damaging and threshold concentrations. For more precise characteristics Chemical toxicants use the concept of “toxodose,” which characterizes the amount of a toxic substance absorbed by the body over a certain period of time.

According to the degree of impact on the human body, hazardous chemicals are divided into 4 hazard classes: 1 - extremely dangerous; 2 - highly dangerous; 3 - moderately dangerous; 4 - low-risk.

In terms of their damaging properties, hazardous chemicals are heterogeneous. As their main classification sign The most commonly used symptom is the predominant syndrome that develops during acute intoxication of a person.

Based on this, according to the nature of the impact on the human body, all hazardous substances are conventionally divided into the following groups:

• substances with a predominantly asphyxiating effect (chlorine, phosgene, etc.);
• substances with predominantly general toxic effects (carbon monoxide, etc.);
• substances that have a suffocating and generally toxic effect (nitric acid and nitrogen oxides, sulfur dioxide, hydrogen fluoride, etc.);
• substances that have a suffocating and neurotropic effect (ammonia, etc.);
• metabolic poisons (ethylene oxide, etc.);
• substances that disrupt metabolism (dioxins, etc.).

Dangerous chemicals are found in large quantities in enterprises that produce or consume them. In chemically hazardous enterprises, they are feedstock, intermediate, by-products and final products, as well as solvents and processing agents. Stocks of these substances are placed in storage facilities (up to 70-80%), technological equipment, and vehicles (pipelines, tanks, etc.). The most common hazardous chemicals are liquefied chlorine and ammonia. Some chemical waste facilities contain tens of thousands of tons of liquefied ammonia and thousands of tons of liquefied chlorine. In addition, hundreds of thousands of tons of hazardous chemicals are transported around the clock by rail and pipeline transport.

Chemical accidents

The danger at chemical waste facilities is realized in the form of chemical accidents. A chemical accident is an accident at a chemically hazardous facility, accompanied by a spill or release of hazardous chemicals, which can lead to death or chemical contamination of people, food, food raw materials and feed, farm animals and plants, or to chemical contamination of the natural environment. During chemical accidents, hazardous substances spread in the form of gases, vapors, aerosols and liquids.

As a result of the instantaneous (1-3 minutes) transition of part of the substance from the container into the atmosphere upon its destruction, a primary cloud is formed. A secondary cloud of hazardous substances is a result of the evaporation of a spilled substance from the underlying surface. Chemical emergencies of this type occur during emergency releases or spills of liquefied ammonia and chlorine used in production, stored or transported.

As a result of a chemical accident with the release of hazardous substances, chemical contamination occurs - the spread of hazardous chemicals in the environment natural environment in concentrations or quantities that pose a threat to people, farm animals and plants over a specified period of time.

The possible release of a cloud of contaminated air outside the territory of a chemically hazardous facility causes a chemical hazard for the administrative-territorial unit where such an object is located. As a result of an accident at a chemical facility, a zone of chemical contamination appears.

Chemical contamination zone- territory and water area within which hazardous chemicals are distributed or introduced in concentrations or quantities that pose a danger to human life and health, for farm animals and plants for a certain time.

In the zone of chemical contamination, its constituent zones can be distinguished - the zone of fatal toxodoses (zone of extremely dangerous contamination), the zone of damaging toxodoses (zone of dangerous contamination) and the zone of discomfort (threshold zone, zone of contamination).

At the outer edge of the lethal toxodiasis zone, 50% of people receive a lethal toxodose. At the outer limit of damaging toxodoses, 50% of people get a damaging toxodose. At the outer border of the discomfort zone, people experience discomfort, exacerbation of chronic diseases begins, or the first signs of intoxication appear.

At the source of chemical contamination, massive injuries occur to people, farm animals and plants.

In case of accidents at chemically hazardous facilities, a complex can be used damaging factors: directly at the accident site - toxic effects of hazardous substances, shock wave in the presence of an explosion, thermal effects and effects of combustion products in a fire; outside the accident site - in areas where contaminated air is distributed, there is only a toxic effect as a result of chemical contamination of the environment. The main damaging factor is the toxic effects of hazardous substances.

Consequences of accidents

The consequences of accidents at chemical waste facilities are the totality of the results of the impact of chemical contamination on facilities, the population and the environment. As a result of the accident, a chemical emergency situation develops and a man-made emergency arises.

People and animals suffer damage as a result of hazardous substances entering the body: through the respiratory system - inhalation; skin, mucous membranes and wounds - resorptive; gastrointestinal tract - orally.

The degree and nature of the impairment of the body’s vital functions(damages) depend on the characteristics of the toxic effect of hazardous substances, their physico-chemical characteristics and state of aggregation, the concentration of vapors or aerosols in the air, the duration of their exposure, and the routes of their penetration into the body.

Mechanism of toxic action The danger is as follows. Intensive metabolism occurs inside the human body, as well as between it and the external environment. The most important role in this metabolism belongs to enzymes (catalysts), present in all living cells and carrying out the transformation of substances in the body, thereby directing and regulating its metabolism. Numerous biochemical reactions in cells are carried out by a huge number of different enzymes. The toxicity of certain hazardous substances lies in the chemical interaction between them and enzymes, which leads to inhibition or cessation of vital functions of the body. Complete suppression of certain enzyme systems causes general damage to the body, and in some cases its death.

Most often, disorders in the body manifest themselves in the form of acute and chronic poisoning occurring as a result of inhalation of hazardous substances into the human body. This is facilitated by the large surface of the lung tissue, the rapid penetration of hazardous substances into the blood, increased pulmonary ventilation and increased blood flow in the lungs during work, especially physical work.

Environmental consequences of accidents and disasters at facilities with chemical technology are determined by the processes of distribution of harmful chemicals in the environment, their migration in various environment-forming components and those changes that are the result of chemical transformations. These transformations, in turn, cause changes in the conditions and nature of certain natural processes and disturbances in ecosystems.

Features of chemical protection of the population

Chemical protection is a set of measures aimed at eliminating or reducing the impact of hazardous chemicals on the population and personnel of chemical facilities, reducing the scale of the consequences of chemical accidents.

Chemical protection measures are carried out, as a rule, in advance, as well as promptly during the liquidation of emerging chemical emergencies.

The following chemical protection measures are carried out in advance:

• systems for monitoring the chemical situation in areas of chemically hazardous facilities and local warning systems for chemical hazards are created and operated;
• action plans are developed to prevent and eliminate a chemical accident;
• Personal protective equipment for respiratory organs and skin, chemical reconnaissance devices, and degassing substances are accumulated, stored and maintained in readiness;
• shelters are maintained in readiness for use, ensuring the protection of people from hazardous chemicals;
• measures are being taken to protect food, food raw materials, fodder, sources (supplies) of water from contamination with hazardous chemicals;
• training is being carried out to act in conditions of chemical accidents of emergency rescue units and personnel of chemical enterprises;

ensures the readiness of forces and assets of subsystems and units of the RSChS, on the territory of which chemically hazardous objects are located, to eliminate the consequences of chemical accidents.

The main chemical protection measures include:

• detection of a chemical accident and notification of it;
• identification of the chemical situation in the zone of a chemical accident;
• compliance with behavior regimes in the contaminated area, chemical safety standards and regulations;
• provision of the population, personnel of the emergency facility and participants in the liquidation of the consequences of a chemical accident with personal protective equipment for the respiratory system and skin, and the use of these means;
• evacuation of the population, if necessary, from the accident zone and areas of possible chemical contamination;
• sheltering the population and personnel in shelters that provide protection from hazardous chemicals;
• prompt use of antidotes (antidotes) and skin treatments;
• sanitary treatment of the population, personnel and participants in the liquidation of the consequences of accidents;
• degassing of an emergency facility, territory, facilities and other property.

Notification of a chemical accident should be carried out by local warning systems. The decision to notify personnel and the public is made by the duty shifts of dispatching services for emergency chemical hazardous facilities.

In case of accidents, when it is predicted that the damaging factors of hazardous chemicals will spread outside the facility, the population, managers and personnel of enterprises and organizations falling within the boundaries of local warning systems (within a 1.5-2 km zone around the chemical hazardous facility) are notified.

In case of large-scale chemical accidents, when local systems do not provide the required scale of warning, territorial and local systems centralized notification. In addition, currently only about 10-12% of chemically hazardous facilities in Russia have local warning systems.

When a chemical accident occurs, in order to implement specific protective measures, the chemical situation in the zone of the chemical accident is identified; chemical reconnaissance is organized; the presence of hazardous substances, the nature and volume of the release are determined; direction and speed of movement of the cloud, time of arrival of the cloud to certain objects of industrial, social, residential purposes; the territory covered by the consequences of the accident, including the degree of its contamination with hazardous substances and other data.

In case of chemical accidents, personal protective equipment is used to protect against hazardous chemicals. The main means of individual protection of the population from inhalation hazardous chemicals are civilian gas masks GP-5, GP-7, GP-7V, GP-7VM, GP-7VS. All these products have a major drawback - they do not protect against certain hazardous chemicals (ammonia vapor, nitrogen oxides, etc.). To protect against these substances, additional cartridges for gas masks DPG-1 and DPG-3 are used, which also protect against carbon monoxide.

There is currently a serious the problem of timely provision of personal protective equipment to the population respiratory organs in conditions of chemical accidents. To protect against hazardous chemicals, the products must be issued to the population as soon as possible, however, due to the remoteness of the storage locations, the time for their issuance can range from 2-3 to 24 hours. During this period, the population caught in the zone of chemical contamination may receive injuries of varying degrees of severity.

Timely evacuation of the population from possible areas of chemical contamination can be carried out proactively and urgently. Preemptive (advance) evacuation is carried out in cases of threat or during long-term large-scale accidents, when the threat of the spread of a chemical contamination zone is predicted. Emergency (immediate) evacuation is carried out in conditions of rapid reactions in order to urgently clear the area from people in the direction of the spread of the cloud of hazardous substances.

An effective way of chemical protection of the population is shelter in civil defense protective structures, primarily in shelters that provide respiratory protection from hazardous chemicals. This method of protection is especially applicable to personnel, since a significant part of chemically hazardous facilities (up to 70-80%) have shelters various classes. Reliable protection of those being covered can be provided for up to 6 hours. Then those being sheltered must be taken out of the shelters, if necessary - to individual means protection. Currently, the use of shelters during chemical accidents is complicated by the reduced efficiency of air purification equipment. Due to the crisis in the economy, the production of this type of equipment has been discontinued or its production volumes have been reduced, and the shelf life of filter ventilation installations in shelters has in most cases expired or is close to it.

In this regard, in the conditions of a chemical accident, in some cases it is more advisable to use residential, public and industrial buildings, as well as vehicles, in or near which people are located, to protect people. It should be taken into account that hazardous chemicals heavier than air (chlorine) will penetrate into the basements and lower floors of buildings, and hazardous chemicals lighter than air (ammonia) will fill the higher floors of buildings. The less air exchange in the room used for protection, the higher its protective properties. As a result of additional sealing of window, door openings and other building elements, the protective properties of premises can be increased by 2-3 times.

When sheltering indoors, feeling signs of the appearance of hazardous chemicals, you must immediately use a gas mask, simple or available personal protective equipment. You should not panic, since the threshold for sensing toxic chemical vapors is significantly lower than their damaging concentration.

All those taking refuge in buildings must be prepared to leave the contaminated zone according to the instructions of the civil defense authorities or independently (if the risk of exit is justified).

When making a decision to independently exit (or receive instructions to exit) from the infected zone, it should be taken into account that its width, depending on the distance from the source of infection and weather conditions, can range from several tens to several hundred meters, which can be overcome along the shortest path - perpendicular to the direction wind may take no more than 8-10 minutes. This time may be enough for a safe exit even in the simplest personal protective equipment.

Thus, it is possible to reduce possible losses and protect people from the damaging factors of accidents at chemical waste facilities by carrying out a special set of measures. Some of these activities are carried out in advance, others are carried out constantly, and others are carried out with the emergence of the threat of an accident and with its onset.

Activities carried out constantly include monitoring the chemical situation both in the chemical waste facilities themselves and in the territories adjacent to them. The chemical situation refers to the presence in the environment of a certain amount and concentration of various chemically hazardous substances.

Control of the chemical situation is carried out in all elements of the biosphere: atmospheric air, lithosphere soil, hydrosphere. The main focus is on controlling air pollution as a determining factor chemical pollution the entire environment.