Breath poison

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Breath poisons are primarily substances that have a harmful effect on humans if they are absorbed through the airways .

In the strict sense of the word, contact poisons do not count as breath poisons, as these are primarily absorbed through the skin.

The effect of the breath poisons is very different, but in principle depends on the concentration and the duration of exposure. The damaging effect can lead to immediate death (e.g. hydrocyanic acid fumes ) or to chronic damage (e.g. in the case of asbestos ).

Classification of breath poisons

Breath poisons can be classified based on their damaging properties. The breath poisons are divided into 3 groups according to their main effect:

In addition, a distinction is made between respiratory poisons in terms of their solubility in water, their molar mass (lighter or heavier than air), and last but not least, their physical state (solid, liquid, gaseous)

Breath poisons with a suffocating effect

These respiratory toxins are not actually poisonous, but displace the oxygen necessary for breathing in high concentrations . For example, inert gases are used in the chemical industry to prevent an explosive gas mixture from forming in storage tanks. The presence of inert gases or the lack of the necessary oxygen in the ambient air cannot be perceived with the human sensory organs. According to the definition of the term poison, such gases are actually not poisons, because they do not work in “comparatively small doses”.

Effects of insufficient oxygen content in the inhaled air

Oxygen content Nitrogen gas content effect
21% - 17% 79% - 83% no impairment of breathing
17% - 13% 83% - 87% Signs of fatigue
13% - 10% 87% - 90% Shortness of breath
10% - 8% 90% - 92% unconsciousness
<8% > 92% death

Examples of gases with a suffocating effect at too high a concentration are: Nitrogen , hydrogen and noble gases such as B. argon and helium .

The only protection is the wearing of self-contained breathing apparatus, e.g. compressed air breathing apparatus .

Breathing poisons with irritating and corrosive effects

These irritate or destroy the tissue of the airways and often cause long-term damage. They are divided into easily and hardly soluble in water. The easily water-soluble respiratory toxins react in the upper respiratory tract ( mouth , nose , throat , larynx) and have a damaging effect there. The poorly water-soluble respiratory toxins get into the lower airways ( trachea , left and right main trachea branches, bronchi , bronchioles and alveoli ) and there, after a latency period, have a damaging effect on the body, leading to pulmonary edema .

This means that easily water-soluble irritant toxins are less dangerous than poorly water-soluble ones. Apart from the caustic effect, easily water-soluble irritant gases are already perceived by humans in harmless concentrations, so that protective measures can be implemented in good time.

Examples are: acid vapor , ammonia , nitrogen oxides , caustic vapors , phosgene , dusts of potash or caustic soda .

Breath poisons affecting blood, nerves and cells

These respiratory toxins are absorbed into the blood by the respiratory organs , where they act in other organs of the body or cause direct brain damage. They can also influence the transport of oxygen in the blood (carbon monoxide, which binds to the hemoglobin ).

Examples are: carbon monoxide , carbon dioxide , hydrogen cyanide , alcohols , hydrogen sulfide , carbon disulfide and the chemical warfare agents tabun , soman , sarin , VX .

In principle, these breath poisons can also be absorbed through the skin. But since this happens much more slowly, the risk of absorption through the airways is greater.

Hydrogen cyanide (also cyanide (HCN short)) is the in the fire department usual HuPF soaked spongy -Clothes and damages the body very quickly. While still on the scene, fainting caused by internal suffocation can result in death. Hydrocyanic acid prevents the exchange of oxygen between the blood and cells, accident victims must be treated by an emergency doctor as soon as possible and must be taken to a hospital for observation.

Carbon dioxide does not belong in group 1, as is often mistakenly assumed, but in group 3, since respiration in healthy people is regulated by carbon dioxide. The carbon dioxide content in the blood is measured by the elongated medulla ( medulla oblongata ), which regulates the respiratory reflex. An increase in the carbon dioxide content in the air you breathe initially has an effect that increases the breathing frequency and depth of breathing, but with a further increase in the concentration in the air it turns into respiratory paralysis with unconsciousness and subsequent death. Carbon dioxide therefore has a direct impact on nerves and blood.

Protection against respiratory toxins

Suitable respiratory protection must be used at locations where respiratory toxins are to be expected . Various mask types with different respiratory protection filters are available for this.

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  1. ↑ LPN-San 2nd edition ISBN 3-938179-57-0

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