Accidents at chemically hazardous facilities. Akhov: classification


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 highly dangerous chemical compound that is used in industry or agriculture, when released into the air or onto the soil, infection can occur, and as a result, a negative effect begins to affect all living organisms.

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

Today all over the world they produce hazardous substances in large quantities, on the territory 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 substances; 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 high temperature have the ability to degas naturally. But volatility directly depends on the boiling point at atmospheric pressure and 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 area. 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. As the main damaging effect, the sign of the predominant syndrome, which occurs during an acute form of intoxication of the human body, is most often used. 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

The characteristics of hazardous chemicals according to physical properties are determined 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 observe 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 the same amount is transported by railway 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 in the right conditions, a chemical accident may occur. Today we can identify 9 main substances that pose an extreme danger to humans and environment, among them most often - chlorine, ammonia, hydrogen sulfide, carbon disulfide, hydrogen fluoride.

Impact of hazardous substances on humans

A chemical accident can lead to the release of hazardous and toxic substances into 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

Determine the outlier yourself chemical substances maybe the person himself. 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 ammonia refrigerant;
  • 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 activities related to chemical protection should 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;
  • the readiness of the RSChS forces to eliminate the consequences of chemical accidents is ensured.

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 substances

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.

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 hazardous chemical substances (HAS) into the atmosphere. material damage and great loss of life. As statistics show, in last years On the territory of the Russian Federation, 80-100 accidents occur annually 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 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"ABOUT industrial safety dangerous 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 chemically hazardous facilities operating in the country, 148 cities are located in zones of increased chemical danger. 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 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 a more accurate description of hazardous substances, the concept of “toxodose” is used, 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 feature, the sign of the predominant syndrome that develops during acute intoxication of a person is most often used.

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 chemicals, chemical contamination occurs - the spread of hazardous chemicals in the natural environment in concentrations or quantities that pose a threat to people, farm animals and plants for a certain 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 waste 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 and exacerbation begins chronic diseases or the first signs of intoxication appear.

At the site of chemical contamination, mass casualties people, farm animals and plants.

In case of accidents at chemically hazardous objects, a complex of damaging factors may operate: directly at the accident site - the toxic effects of hazardous chemicals, a 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 poisonings that occur 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;
  • funds are accumulated, stored and maintained in readiness personal protection respiratory organs and skin, chemical reconnaissance devices, degassing substances;
  • 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, norms and rules chemical safety;
  • 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, 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 centralized warning systems are used along with them. 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 release are determined; direction and speed of movement of the cloud, time of arrival of the cloud to certain objects of industrial, social, and 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 the population with personal protective equipment respiratory organs in conditions of chemical accidents. To protect against hazardous chemicals, funds must be issued to the population in as soon as possible, however, due to the remoteness of storage locations, their issuance time 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 a shelter in protective structures civil defense, 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 of 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, and vehicles, inside or near which there were 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.

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 conditions environment.

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 (connections heavy metals, ethylene glycol, oxalic acid);

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

· pulmonary (nitrogen oxides, ozone, phosgene).

The toxic effect under the influence of various doses and concentrations of hazardous substances can manifest itself 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 values ​​of the thresholds for harmful effects (one-time, chronic) and the threshold for specific effects).

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 the whole body or affecting individual systems (central nervous system, hematopoiesis), causing pathological changes in the liver, 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 for contamination of the ground layer of the atmosphere is determined by their physical and chemical properties, as well as their ability to go into 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 also sharply decreases ( a liquid nitrogen). 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 at elevated temperature and pressure (benzene, toluene).

Currently, the chemical industry occupies one of the leading places in the country's economy. Its enterprises process various Natural resources and create new types of raw materials and various goods: food, plastic products, fuel, medicines, fertilizers and much more. It is difficult to imagine our life without these goods.

At the same time, it should be noted that many chemical compounds used in industrial activities are highly toxic 1 and can, under certain conditions, cause mass poisoning of people and animals, as well as environmental contamination. Such substances are called hazardous chemicals (HCS). Exposure to a hazardous chemical substance on the human body can cause acute or chronic disease or death.

In total, there are more than 600 thousand types of hazardous chemicals currently used in industry, but only a little more than 100 of them are classified as hazardous chemical substances (HAS).

    Remember!
    An emergency chemically hazardous substance is a dangerous chemical substance used in industry and agriculture, the accidental release of which can cause contamination of the environment in concentrations that can affect a living organism.

In total, 10 of the most common hazardous substances were noted. Among them are ammonia, hydrazine, dioxin, carbon monoxide, ethylene oxide, carbon disulfide, sulfur dioxide, phosgene, chlorine, hydrogen cyanide.

Economic facilities that produce, consume, or store hazardous chemical substances are classified as chemically hazardous facilities.

    Remember!
    A chemically hazardous object is an object, in the event of an accident or its destruction, massive injuries to people, animals and plants from emergency chemically hazardous substances can occur.

Statistics

In the Russian Federation, there are over 3.3 thousand chemically hazardous economic facilities that have significant quantities of hazardous substances. The total stock of hazardous chemicals at enterprises reaches 700 thousand tons. Such enterprises are often located in large cities (with a population of over 100 thousand people) and near them. Over 70% of chemical enterprises and almost all enterprises of the petrochemical and oil refining industries are concentrated here.

The total area of ​​Russian territory where chemical contamination may occur is about 300 thousand km 2 with a population of about 59 million people.

It should be noted that more than 50% of chemically hazardous facilities use and store ammonia, 35% - chlorine, 5% - hydrochloric acid.

In particular, ammonia and chlorine are widely used in the metallurgical, food, medical industries, public utilities and agriculture.

    Attention!
    Significant reserves of ammonia and chlorine are concentrated in the food and meat and dairy industries, in refrigerators of shopping centers, and in housing and communal services. Thus, vegetable warehouses contain up to 150 tons of ammonia, used as a refrigerant, and water treatment stations contain from 100 to 400 tons of chlorine. In addition, statistics show that ammonia and chlorine are the most dangerous substances in terms of the number of deaths.

The damaging factors of all hazardous chemicals are their toxic effects on the human and animal body. People and animals suffer damage as a result of hazardous substances entering the body through the respiratory system, skin, mucous membranes, wounds and the gastrointestinal tract (with food).

The mechanism of the toxic effect of hazardous substances on the body is the chemical interaction between hazardous substances and the body’s enzymes. Enzymes are specific biological protein catalysts present in living organisms and capable of accelerating the chemical reactions occurring in them many times over. Thanks to enzymes, chemical reactions in cells form a single, strictly coordinated system called metabolism and energy.

We know that an intensive exchange of substances and energy occurs inside the human body, as well as between it and the external environment. The chemical interaction of hazardous substances with enzymes leads to inhibition or cessation of a number of vital functions of the body. Complete suppression of certain enzyme systems of the body can cause general damage to the body, and in some cases its death.

It should be noted that in our country a whole range of measures is being implemented to ensure the safe operation of the chemical industry and, in general, all branches of the chemical industry work smoothly and safely, producing the necessary products. But it is not possible to completely eliminate emergency situations at chemically hazardous facilities. Unfortunately, accidents at chemically hazardous facilities happen all the time. Thus, according to the Russian Ministry of Emergency Situations, chemical accidents with the release or threat of release of hazardous substances at chemically hazardous facilities in our country occurred in 2008 (17 accidents).

    Remember!
    A chemical accident is an accident at a chemically hazardous facility, accompanied by a spill or release of an emergency chemically hazardous substance, which can lead to death or chemical contamination of people, farm animals and plants, and chemical contamination of the natural environment.

As a result of a chemical accident with the release of hazardous substances, a source of chemical damage is formed.

Damage to humans occurs through the respiratory system, skin, mucous membranes, and gastrointestinal tract.

    Remember!
    The source of destruction of hazardous substances is the territory within which, as a result of exposure to hazardous substances, mass damage to people, animals and plants occurred.

As a result of an accident, several damaging factors may act at the facility: chemical contamination of the area, air, and water bodies; high or low temperature; during an explosion - a shock wave.

The most dangerous damaging factor of a chemical accident is exposure to hazardous chemical vapors through the respiratory system. They act both at the scene of the accident and at large distances from the source of the release. The cloud of hazardous chemical vapors spreads at the speed of their wind transfer. Dangerous concentrations of hazardous substances in the atmosphere can exist from several hours to several days, and on the ground - for an even longer time.

    Attention!
    Emergency Situations Ministry experts believe that technology violations are the main causes of chemical accidents production work, as well as the “human factor” (violation of production discipline and safety regulations, inefficiency production control for compliance with safety requirements for the production of chemicals).

Limited (local) accidents at chemically hazardous facilities are not so rare, but sometimes accidents with catastrophic consequences occur.

Historical facts

The most tragic consequences were caused by a chemical accident that occurred at a chemical plant in the city of Bhopal (India). On the night of December 2-3, 1984, as a result of a technological accident, a liquefied substance violently escaped from underground tanks, turning into a volatile gas. More than 40 tons of methyl isocyanide, a highly toxic gas that serves as an intermediate product in the manufacture of pesticides, leaked. A toxic cloud covered 40 km 2 city blocks. The wind was not strong at that time, and the deadly cloud did not spread further.

As a result of this chemical accident, about 2.5 thousand people died, over 500 thousand were seriously poisoned. The crops within a radius of 200 km were completely destroyed.

A chemical accident, which, according to experts, has no analogues in world practice in terms of the scale of release of hazardous chemical substances, occurred on March 20, 1989 at the Azot production association in the city of Ionova (Lithuania, USSR).

The company produced organic resins, methanol, ammonia and mineral fertilizers. Over 500 thousand tons of ammonia were produced per year. All ammonia orders were stored in a tank with a capacity of 10 thousand tons and in two more tanks of 400 tons, which are isothermal (providing a constant temperature) storage facilities.

The temperature of liquefied ammonia 2 in the storage was -34 "C.

The chemical accident occurred at 11:15 a.m. in an isothermal storage facility and was accompanied by an immediate release of 7 thousand tons of liquefied ammonia into the environment. As a result of the accident, a reinforced concrete tank containing liquefied ammonia was destroyed. It spread unhindered throughout the plant, forming a lake of toxic liquid with an evaporation surface of about 10,000 m2.

Due to the unforeseen nature of the accident, accompanied by the formation of a large-area source of chemical contamination, a complex and dangerous chemical situation was created at the facility itself and the adjacent territory. The area of ​​the infection zone, where there was a real threat of injury to people, reached certain periods accident development of several hundred square kilometers.

Only the adoption of prompt and effective measures at all levels made it possible to avoid major casualties, but nevertheless, as a result of the accident, 7 people died, 57 people received injuries of varying degrees of severity.

In conclusion, it should be noted that the chemical industry will undoubtedly continue to develop, satisfying the needs of the population for various types of goods, which means that the number of chemically hazardous enterprises will increase. It's unavoidable. At the state level, appropriate measures will be taken to ensure the chemical safety of the population. In addition, efforts are needed to improve the level of chemical safety of the population, especially those living in places where chemically hazardous facilities are located.

Questions

  1. What role does the chemical industry play in meeting human needs?
  2. What chemicals are classified as hazardous chemical substances (HAS)?
  3. Which economic facilities are considered chemically hazardous?
  4. What consequences can the impact of hazardous chemicals have on the human body?
  5. What is a chemical accident? List its possible consequences.

Exercise

Find out whether there is a chemically hazardous facility near your place of residence and what products it produces. Familiarize yourself with the rules for notifying the public in the event of a chemical accident at a facility. Make appropriate notes in your notebook about personal safety rules in the event of an emergency in your area of ​​residence.

1 Toxicity is the ability of certain chemical compounds to have harmful effects on human, animal and plant organisms.

2 Ammonia (NH 3) is a colorless toxic gas with a characteristic pungent odor (ammonia). Specific gravity in the liquid state is 0.682 g/cm 3, storage temperature is 33.35°C. The concentration of danger of acute poisoning for humans is 0.3 mg/l. The presence of ammonia in the air can be easily determined by its smell.

Evolution and progress have not rid humanity of hazardous substances used in industry and agriculture. Approximately 8.5 million chemical compounds not found in natural habitats have been invented to date. Most of them are synthesized from petroleum products. There are approximately 500 chemicals used by humans in economic activity, are recognized as toxic substances. Those of them that, when released into the air or soil, cause extreme harm to health, infect and poison the body, are called hazardous chemical substances.

List of emergency chemical hazardous substances

The main damaging factors and effects on the human body are given in a separate card for a chemically hazardous substance.

No. Name Hazard Class
1. 3
2. 3
3. 2
4. 2
5. 4
6. 3
7. 3
8. 2
9. 2
10. 2
11. 1
12. 1
13. 2
14. 1
15. 2
16. 1
17. 2
18. 3
19. 2
20. 2
21. 1
22. 2
23. 2
24. 3
25. 2
26. 2
27. 2
28. 1
29. 2
30. 1
31. 2
32. 1
33. 2
34. 1
35. 1
36. 2

Where is Akhov found?

The most common hazardous substances are found in the following places:

  1. At oil refining enterprises.
  2. In warehouses. In workshops with refrigeration equipment running on ammonia.
  3. Engineering structures designed to clean water supply and sewerage systems where chlorine is still used.

In the process of destruction or deformation of the containers in which these poisons were located, or in the event of the release of hazardous chemicals into the atmosphere, their penetration into the human body through the respiratory, digestive, skin and mucous membranes begins.

The main characteristic of these substances is that they have a relative density. If the density of a toxic substance is less than one, then it will have a high dissipation rate because the air will be heavier. In cases where the density exceeds 1, such hazardous substances are able to remain below, near the ground, longer.

According to danger they are divided into 4 classes:

  1. Possessing extreme danger. Even a small amount can cause the death of a living creature. This is mercury, ethyleneimine.
  2. Highly dangerous. This class includes arsenic-containing substances, fluorine, and hydrocyanic acid.
  3. Moderately dangerous
  4. Possessing a slight danger to the environment. For example, acetone.

The process of localizing and eliminating leaks of hazardous chemicals

Types and effects of toxic compounds

The clinical picture will depend on what type of substances are released into the environment. They are divided into asphyxiating and generally poisonous, as well as with a cauterizing effect. In addition, there are neurotropic poisons. They have a destructive effect on nervous system person. These are carbon disulfide and organophosphorus compounds.

IN separate group Chemical poisons include metabolic poisons.

  • Having alkylating activity
  • Destroying the normal metabolic process

These substances have a toxic effect on the body when they get inside along with food and water, get on the skin and when their particles are inhaled.

The action of each poison is specific:

  • ammonia (the characteristic smell of this colorless gas is familiar to many) causes signs of suffocation, coughing, cardiac arrhythmia, increased pulsation rates, redness of the skin and mucous membranes, their itching, tearing of the eyes, frostbite of the skin, and the appearance of burn blisters;
  • chlorine (yellow-green gas with a characteristic odor) causes sharp pain in the chest, excessive lacrimation, vomiting, dry cough and impaired coordination of movements;
  • Hydrogen sulfide (a colorless gas with a specific odor) causes headache, fear of light, lacrimation, vomiting and nausea, a metallic taste in the mouth, and cold sweating.

In addition to the above, substances such as sulfur dioxide, methyl mercaptan, acrylic acid nitrile, hydrocyanic acid, benzene, hydrogen bromide and others are often found.

Visually detectable signs of chemical contamination of the area

  1. The appearance of a cloud that grows for no apparent reason.
  2. Foreign odors leading to suffocation.
  3. Malaise, up to loss of consciousness.
  4. Rapid decline of vegetation.
  5. Death of small animals and birds.

If such signs occur, you should use a gas mask and take cover in a place where it is difficult for air from the environment to enter. Eliminate existing gaps in the shelter, close the ventilation. You should also turn off household appliances. Wearing glasses, for example, sunglasses, will protect the mucous membranes of the eyes. Respiratory organs can be protected with cotton gauze bandages. It's better to have them in your arsenal!

In the event that accidental poisoning with chemically hazardous substances occurs, for example, due to chlorine emissions, the victims are evacuated as quickly as possible to fresh air, to a place where the wind direction is opposite to the source of injury.

First aid when dispatching hazardous substances

Cards of emergency chemical hazardous substances, as well as detailed first aid for emergency poisoning with hazardous chemical substances is presented separately for each type of substance in the table above; by clicking on its name, the chemical properties and characteristics of hazardous chemical substances will additionally be presented.

It should be remembered that in case of ammonia poisoning, artificial respiration is contraindicated, and it matters in what position the victim is transported (strictly in a supine position).

In case of hydrogen sulfide poisoning, urgent washing of the face and eyes is indicated clean water. In any case, all poisoned persons must be taken to the nearest emergency room. Severe inhalation exposure to agents can lead to toxic, rapidly progressive pulmonary edema, incompatible with life.

Medical and veterinary stations will be equipped with these equipment to accurately determine the presence of hazardous substances in water, soil, and food products. To determine the composition of air, professional gas analyzers are needed.