Chemical Injuries

Many chemicals present a serious hazard of causing a chemical injury

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At home, products such as drain cleaners, oven cleaners, brick cleaners and rust removers, have the potential to cause a chemical injury if they come into contact with the skin or the eye.

At work, the risks increase significantly because of the volume, concentration and variety of chemicals increases.

Associated problems are:

• Being able to identify the chemical.
• The lack of knowledge regarding the chemical’s mechanism.
• The lack of synergy between the chemical and the emergency management protocol.

The consequences following a splash with an aggressive chemical can result in a chemical injury (lesion)

Which chemical products cause a chemical Injury (lesion)?

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The chemical products that may cause a chemical lesion are categorised according to the seriousness of the lesions that they may induce: they are either corrosive or irritant.

A chemical product is classified among corrosive or irritant agents when it is capable of reacting with biochemical components of the cells and the tissues of the skin, the eye and the respiratory or digestive tracts. The CLP/GHS regulations of the European Chemicals Agency provide the following definitions of corrosive or irritant products (CLP page L 353/87):

Skin corrosion means the production of irreversible damage to the skin, namely, visible necrosis through the epidermis and into the dermis, following the application of a test substance for up to 4 hours.

The reversibility of the skin lesions is to be considered in assessing the irritant nature of a substance.

A chemical is considered corrosive when it causes a severe lesion. Corrosive products cause destruction of the tissues with which they come into contact. A chemical will be considered irritant if it only causes irritation, redness or inflammation.

The same chemical product may be corrosive or only irritant depending on the circumstances:

• If present in a mixture or on its own
• Depending on its concentration
• Depending on the environment in which it is present

Some chemicals have the additional potential to cause other problems to human health such as those classified as toxic or harmful.

The hazard that a chemical product represents is indicated on its label by the manufacturer according to the regulatory obligations of the European Chemicals Agency.

What is the mechanism of a chemical lesion?

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It all begins with a chemical reaction between two molecules. On a microscopic level, the chemical lesion results from a chemical reaction between an aggressive chemical product and a biological constituent.

This reaction destroys the biological constituent and hence the tissue, this forms the chemical lesion.

The mechanism involved in development of the lesion depends on many parameters, the most significant of which is the nature of the reaction initiated.

Depending on its type, each chemical product will react with a different component of the biological tissue by means of one of following actions:

• Acid-base reaction: H+ proton exchange reaction between an acid and an alkali.
• Redox reaction: electron exchange reaction between an oxidising agent and a reducing agent.
• Chelation: or formation of a complex from two molecules.
• Solvation: dissolution of a chemical species in a solvent.