Chemical hazard class: list, use and general toxic effect

It is impossible to imagine modern life and production without chemicals. With close contact with them, a certain effect is exerted on the human body. It should be noted that there are also such compounds that will manifest their influence after a certain period of time. In the article, we will try to figure out what chemical factors and hazard classes exist. harmful substances as well as how they affect the human body.

Human use of chemicals

Now several million chemical compounds are known, and most of them are used by people in various industries. Seen from the point of view of application hazard classes chemicals list may look like this:

1. Toxic substances used in industry. These include: dyes (aniline), among solvents it is dichloroethane, for example.
2. In the agricultural industry, pesticides are widely used.
3. Chemical compounds that are used in everyday life: hygiene products, for sanitization.
4. Poisonous substances of natural origin, for example, poisons of plants and animals.
5. Poisoning substances: mustard gas, phosgene and others.

Different hazard classes of harmful chemicals can enter the body through the respiratory system, skin or mucous membranes. Substances can exert their negative influence selectively, that is, on a certain system of organs. For example, lead affects the human reproductive system, and nitrogen oxides can trigger pulmonary edema.

Toxic effects of chemicals

If we consider the hazard class of chemicals, GOST identifies several groups. Each has its own units.

Five classes are distinguished depending on the toxic effects and the average lethal dose.

1. The first hazard class includes compounds, which are required very little to damage the body. For example, when ingested through the stomach, this amount is 50 mg per kilogram of human weight.
2. Grade 2 includes substances whose concentration may be higher in order to provoke a toxic effect. It can be from 5 to 50 mg per m3 if it comes through the skin or gastrointestinal tract.
3. Classes 3 and 4 include compounds that are required more than the first two classes and usually make up up to 5000 units.
4. The fifth class includes substances that cause deep toxic damage.

Chemicals and organ of vision

If we take into account the effect of chemicals on the organ of vision, the following classes are distinguished:

1. The first class includes compounds that lead to irreversible changes in the ocular apparatus, and all this ends with visual impairment.
2. The second class contains substances that cause pathological changes in vision, but they can pass within a few weeks.

The effects of chemicals on the skin

There is another classification, it identifies classes of chemicals that have a negative effect on the skin. When dividing the compounds, two criteria were used. Given the first, there are three classes:

• The first group includes substances that lead to visible skin necrosis.
• The second class includes substances that cause reversible damage. In about two weeks, the skin is restored.
• Substances in the third class cause only slight skin irritation, which usually disappears in a couple of days.

The second classification criterion is used in cases where there is insufficient data to classify the substances in the first three groups.

Environmental Impact of Chemical Compounds

According to GOST, there is also a classification that takes into account the effect of chemical compounds on the environment. The following categories of substances are distinguished in this group:

• Fatal to the ozone layer.
• Acute toxic effects on the aquatic environment.
• Substances that have a gradual toxic effect on the inhabitants of water resources.

All these harmful compounds can still be subdivided into categories by harmfulness. To provide a toxic effect, a concentration of 0.1 mg / l is enough.

Classification of chemicals by hazard class

In a huge variety of known substances, not all are equally dangerous to the human body. The following classes are distinguished:

1. The first class includes extremely hazardous substances and compounds. For a fatal outcome, 15 mg of the substance per kilogram of a person’s weight will be enough in the stomach. Examples include the following: potassium cyanide, mercury, nicotine, and others.
2. The second class includes highly hazardous substances. The lethal dosage is from 15 to 150 mg per kilogram of body weight, given the properties of the substance. These compounds have a negative effect not only on humans, but also on the surrounding nature. These include: arsenic, lithium, lead, chloroform.
3. Moderately hazardous - This is the third hazard class of chemicals. For a fatal outcome, 500–2500 mg / kg is sufficient. If ingested through the stomach, the lethal dose is 150-5000 mg / kg of body weight. This class includes: gasoline, aluminum and manganese compounds. Since many substances of this class are often used in everyday life, you can not treat them negligently.
4. Low-hazard substances are the most harmless, since they are distinguished by their low toxicity and danger. These substances often surround us, for example, ammonia can be found in every medicine cabinet, kerosene is used in lamps, ethanol is used in medicine and it is found in alcoholic beverages.

It does not matter how many hazard classes of chemicals exist, it is important to treat everyone with extreme caution, and to observe all safety measures when working with them.

Classification of substances by effects on the body

All available chemicals and compounds differ from each other not only in the degree of toxicity, but also in the nature of human exposure.

Depending on the hazard class, all substances are assigned a specific color.

1. Extremely hazardous substances are marked in red.
2. A high degree of danger is indicated in orange.
3. Moderately hazardous are yellow.
4. Substances that are of low hazard are indicated in green.

Classification of substances in terms of toxic effects

The completely different toxicity of chemicals, hazard classes in connection with this, distinguish the following:

1. Substances that have a nerve-paralytic effect can be attributed here: insecticides, nicotine, sarin.
2. Compounds that cause inflammatory processes and necrotic changes in conjunction with general toxic effects. An example is: vinegar essence, arsenic, mercury.
3. Compounds that cause seizures, coma, cerebral edema, that is, having a general toxic effect. These include: hydrocyanic acid, carbon monoxide, alcohol.
4. Choking agents (fosten, nitrogen oxides).
5. Substances that cause tearing and irritation of the mucous membranes. As an example, we can cite: pairs of acids and alkalis.
6. Substances and compounds that affect the psyche. These include narcotic substances, atropine and others.

If you are to use or come into contact with these substances, special care must be taken.

International classification

We examined how many hazard classes of chemicals exist according to GOST, but there is also a separation based on international requirements. It represents 9 groups, each of which has its own rules for transportation and storage.

1. Substances that can easily explode or catch fire.
2. The second class includes substances that are flammable, toxic, chemically unstable.
3. Chemicals in the liquid state, which are flammable, belong to class 3.
4. Class 4 includes solids capable of self-ignition or fire after external exposure.
5. Organic oxidizing agents belong to the 5th class, as they are capable of releasing oxygen, which supports combustion.
6. Grade 6 - these are toxic substances that cause severe poisoning or death from inhalation of vapors.
7. The next class is radioactive substances.
8. Caustic substances are the eighth hazard class.
9. Grade 9 includes all other substances that did not fall into previous classes, but to some extent can be dangerous.

How to protect yourself from hazardous substances

It is important not only to know the hazard class of chemicals, but also to be able to minimize the degree of influence on the human body and nature. To do this, you can use the following methods:

• To locate toxic and harmful substances in enterprises as far as possible from workplaces.
• Have a modern and efficient ventilation system to remove hazardous substances.
• Use personal protective equipment in a timely manner.
• Use modern water treatment methods before throwing it into the environment.
• Dilute harmful compounds to acceptable concentrations.

The use of these available methods will maximize the safety of humans and nature from exposure to harmful chemicals.

To summarize

If we summarize all that has been said, then we can not only highlight the hazard class of chemicals, but also note the following types of exposure to harmful compounds:

1. Irritating, if it gets on the skin, it causes redness, for example, fluorine, phosphorus, etc.
2. Cauterizing action of the substance can cause burns of varying degrees. These include: ammonia, hydrochloric acid.
3. Choking agents can lead to asphyxiation and death. Phosgene and chloropicrin have this effect.
4. Substances with toxic effects can cause poisoning of varying severity. These include: hydrogen sulfide, hydrocyanic acid, ethylene oxide and others.
5. Mutagenic substances can provoke the appearance of mutations.
6. Carcinogenic effects lead to the development of cancer.

Some classifications also emit narcotic substances, which, getting inside the body, cause addiction and gradual poisoning of the body.

So we got acquainted with the variety of chemicals that surround us almost everywhere. Without chemistry, it is almost impossible to imagine modern industry and production. But in order not to harm your body in the process of interacting with harmful substances, you must be especially careful and know the rules of storage and transportation.