Significantly more SDORs are in the warehouses of enterprises.
mineral and organic acids (sulfuric, nitric, phosphoric, acetic, others); alkalis (ammonia, soda lime, caustic potassium and others); sulfur compounds (dimethyl sulfate, soluble sulfides, carbon disulfide, soluble thiocyanates, chloride and sulfur fluoride); chlorine and bromine-substituted hydrocarbon derivatives (methyl chloride and bromide); some alcohols and acid aldehydes; organic and inorganic nitro and amino compounds (hydroxylamine, hydrosine, aniline, toluidine, nitrobenzene, dinitrophenol); phenols, cresols and their derivatives; heterocyclic compounds.
To moderately toxic, low-toxic and virtually non-toxic chemicals that do not pose a chemical buy compare contrast essay online hazard, includes the bulk of chemical compounds.
It should be noted that a special group of chemically hazardous substances are pesticides – drugs that are designed to control agricultural pests, weeds, etc. Most of them are very toxic to humans.
Most of the chemicals, including those that are mildly toxic (moderately, mildly toxic, and virtually non-toxic), can cause serious injury. At the same time, not all chemical compounds, including extremely, highly toxic ones, can lead to mass sanitary losses as a result of accidents (catastrophes) accompanied by emissions (spills) of chemicals.
Only part of the chemical compounds in the combination of certain toxic and physicochemical properties, such as high toxicity through respiratory action, leather, high tonnage of production, use, storage and transportation, as well as the ability to easily move in emergencies to the main factor (vapor or finely divided aerosol), which can cause human injury. These chemical compounds belong to the group of potent toxic substances (SDOR).
Chemicals that can cause mass damage to the population in accidents with the release (spill) into the air can be divided into groups:
1. Substances with a predominant effect of suffocation:
with a pronounced cauterizing effect (chlorine, phosphorus trichloride, phosphorus oxychloride); with a weak effect of cauterization (phosgene, chloropicrin, sulfur chloride).
2. Substances mainly of general toxic action (carbon monoxide, hydrocyanic acid, dinitrophenol, dinitroorthocresol, ethylene chlorohydrin, ethylene fluorohydrin).
3. Substances which have a suffocating effect and a general toxic effect:
with a pronounced cauterizing effect (acrylonitrile); with a weak effect of cauterization (sulfur dioxide, hydrogen sulfide, nitrogen oxides).
4. Neurotropic poisons, substances that act on the generation, conduction and transmission of nerve impulses (carbon disulfide, organophosphorus compounds).
5. Substances that have a suffocating effect and a neurotropic effect (ammonia).
6. Metabolic poisons (ethylene oxide, methyl bromide, methyl chloride, dimethyl sulfate).
7. Substances that disrupt metabolism (dioxane).
Substances with a predominant suffocation effect are toxic compounds for which the main object of action on the body is the respiratory tract. Lesions of the body under the action of suffocating substances are divided into four periods: the period of contact with the substance, the period of latent action, the period of toxic pulmonary edema and the period of complications. The duration of each period is determined by the toxic properties of each substance and the magnitude of the exposure dose. Under the action of a couple of substances in high concentrations, a rapid lethal end from the state of shock is possible, which is caused by chemical heating of exposed skin, mucous membranes of the upper respiratory tract and lungs.
Substances of mainly general toxic action include compounds that can cause acute disorders of energy metabolism, which in severe cases is the cause of death. These substances can be divided into blood poisons and tissue poisons.
Blood poisons are divided into hemolytic poisons and hemoglobin poisons.
Tissue toxins are divided into inhibitors of respiratory chain enzymes (cyanides, carbon disulfide, acrylonitrile), oxidation and phosphorylation dissociators (dinitrophenol, dinitroorthocresol,) and substances that deplete the reserves of substrates for biological oxidation processes, ethylene hydrochloride.
Substances with a suffocating effect and a generally toxic effect include a significant amount of SDOR, which are able to cause toxic pulmonary edema during inhalation, and to disrupt energy metabolism during resorption. Most of the compounds in this group have a strong cauterizing effect, which makes it much more difficult to provide assistance to victims.
Substances that act on the generation, conduction and transmission of nerve impulses (neurotropic poisons) include substances that disrupt the mechanisms of peripheral nervous regulation, as well as modulating the state of the nervous system. At the heart of their action:
the ability to interfere in the process of synthesis, storage, release, inactivation in the synaptic cleft of neurotransmitters; interact with neurotransmitter receptors; change the permeability of ion channels of excitation membranes.
Substances that have a suffocating effect and neurotropic effect include toxic compounds that cause toxic pulmonary edema during inhalation, against which severe damage to the nervous system is formed.
The basis of the action on the brain is a violation of the generation, conduction and transmission of nerve impulses, which is exacerbated by a state of severe hypoxia caused by a violation of external respiration.
Metabolic poisons include toxic compounds that interfere with the intimate processes of metabolism in the body. Poisoning by these substances is characterized by a lack of reaction to the poison. The defeat of the organism develops, as a rule, gradually and in severe cases ends in death within a few days.
Many organs are involved in the pathological process of these substances, but the main ones are disorders of the central nervous system, parenchymal organs and sometimes the blood system.
By their construction, these substances belong to different classes of compounds, but they all have a common property: in the human body, they are destroyed with the emergence of highly reactive hydrocarbon radicals.
Metabolic substances include toxic compounds of the group of halogenated aromatic carbohydrates. At the same time dibenzodioxanes and polychlorinated benzofurans are marked by the personal biological activity.
These substances are able, acting through the lungs, digestive tract and intact skin, to cause diseases with extremely sluggish passage. In this case, almost all organs and systems of the human body are involved in the process. A characteristic feature of these substances is a metabolic disorder, which can sometimes lead to death.
The factor of chemical hazard is the toxic effect, which is determined by the concentration of a highly toxic substance (SDR) in the environment and the density (density) of chemical contamination of the area and objects of economic activity.
Density (density) of contamination with hazardous chemicals is the degree of chemical contamination of the area.
Strong toxic substances are transported over short distances by vehicles in cylinders, containers and tank trucks. Of the wide range of medium capacity cylinders for storage and transportation of liquid SDOR are used, as a rule, cylinders with a capacity of 0.016 to 0.05 m3. The capacity of the containers varies from 0.1 to 0.8 m3. Tank trucks are used to transport ammonia, chlorine, heptyl and amyl. The standard ammonia truck has a load capacity of 3.2; 10 and 16 tons. Liquid chlorine is transported in tank trucks with a capacity of up to 20 tons, amyl up to 40 tons and heptyl up to 30 tons.
The safety of chemically hazardous facilities depends on many factors: physicochemical properties of raw materials, intermediates and products, the nature of the technological process and reliability of equipment, storage and transportation of chemicals, the state of control and measuring devices and automation, the effectiveness of anti-emergency protection, etc.
In addition, the safety of production, use, storage and transportation of SDOR largely depends on the level of organization of preventive work, timeliness and quality of planned preventive work, training and practical skills of personnel, system of monitoring the condition of technical means against emergency protection.
The presence of a large number of factors on which the safety of chemical hazards depends makes this problem too difficult. According to the analysis of the causes of major chemical accidents, accompanied by the release (spill) of SDOR, today it is impossible to exclude the possibility of accidents that will lead to the production staff and the population located in the area of operation of a chemically hazardous facility.
The analysis of the structure of enterprises that produce or use SDOR shows that in their technological lines, as a rule, a small amount of toxic chemical products rotates. A much larger number of SDORs are in the warehouses of enterprises. This leads to the fact that in accidents in the shops of enterprises in most cases there is a local contamination of the air, equipment of shops, the territory of enterprises. In this case, the defeat in such cases can be received mainly by production personnel.
In case of accidents in the warehouses of enterprises, when tanks are destroyed, SDOR spreads outside the enterprise, which leads to mass destruction not only of the personnel of the enterprise, but also of the population located in the affected area of the business entity.
The capacity of SDOR warehouses at any enterprise is determined depending on the required stock, which ensures the continuous operation of the enterprise, as well as on the appropriate allowable accumulation on the production site of marketable products to be sent to consumers. As a result, SDOR storage rates at each enterprise are determined based on the conditions of their consumption, production, transportation, prevention of emergencies, preventive stops, seasonal deliveries, as well as toxicity, fire and explosion safety.
On average, the minimum (not reducing) stocks of chemical products at enterprises are created for three days, and for plants for the production of certain chemicals and mineral fertilizers – up to 10-15 days.
As a result, thousands of tons of various potent toxic substances can be stored simultaneously in large chemical plants, as well as in warehouses in some ports and in vehicles transporting SDOR.