Skin irritants

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1. What is a skin irritant?

A ‘skin irritant’ is a substance which causes inflammation of the skin, principally a disease known as dermatitis. Skin irritants fall into one of two groups, depending on their potential to cause dermatitis:
 

• primary skin irritants produce direct inflammation on those areas of the skin they come into contact with;
• secondary skin irritants produce similar effects after a period of exposure, the inflammation not being confined to a particular area of the body.

2. What is dermatitis?

Dermatitis is a disease of the skin which can have different symptoms and vary in seriousness. It usually starts with irritation and redness and, occasionally, swelling of the affected area. Blisters sometimes then develop and, when these burst, septic infection can occur. Any part of the body can be affected if it comes into contact with a skin irritant. Dermatitis generally affects the hands and arms, but it can spread to other parts of the body if medical treatment is not sought — its more serious effects are often slow to develop.

There are two main types:

• Irritant contact dermatitis: This can occur quickly after contact with a strong irritant, or over a longer period from repeated contact with weaker irritants. Irritants can be chemical, biological, mechanical or physical. Repeated and prolonged contact with water (e.g. more than 20 hand washes or having wet hands for more than 2 hours per shift) can also cause irritant dermatitis.
• Allergic contact dermatitis: This can occur when the sufferer develops an allergy to a substance. Once someone is ‘sensitised’, it is likely to be permanent and any skin contact with that substance will cause allergic contact dermatitis. Often skin sensitisers are also irritants.

3. Which substances are irritants?

A wide range of substances can irritate the skin, but they usually fall into one of the following groups:
 

• Mineral oils: All types of oil, including diesel and other fuel oils, can cause skin irritation, though some are more likely to cause harm than others. Oils cause a form of dermatitis known as ‘oil acne’, which results in pimples or blackheads on the skin where the pores have become blocked and septic infection has occurred. Oil acne normally only affects those areas which have been in direct contact with either oil or oily clothing.
• Chemicals: Some chemicals, particularly strong alkalis and some acids, penetrate the skin and form ulcers or ‘holes’ which are slow to heal. These include:
  • explosives;
  • some insecticides;
  • chromic acid;
  • chlorinated napthalenes and diphenyls;
  • chromates;
  • bichromates;
  • nickel salts;
  • rubber accelerators;
  • mercury compounds;
  • formaldehyde, a particularly strong skin irritant which can produce a severe form of dermatitis.
• Solvents and degreasers: These can cause dermatitis by dissolving the natural grease from the skin. They also make the skin more prone to damage from other substances. They include:
  • paraffin;
  • turpentine;
  • petroleum products;
  • trichloroethylene;
  • and other solvents.
• Tar, pitch and coal tar products: Long exposure to pitch and tar could result in warts or ulcers which can turn malignant.
• Other substances: Prolonged contact with some other substances has been known to cause dermatitis, including:
  • sugar;
  • certain hardwoods;
  • some types of antibiotics;
  • cement;
  • some flowers.
• Acidic & Alkaline materials: The pH Scale runs from the most acidic (0.0) to the most alkaline (14.0) The pH value of human skin is usually neutral or slightly acidic (approximately pH7). Many common products are significantly alkaline or acidic and lengthy exposure may cause dermatitis.

In the course of normal sampling operations, you are unlikely to be exposed for long periods but if there are spills or damaged packaging your clothing or PPE may become contaminated with apparently innocuous food products, which increases the risk of lengthy exposure.

Remember: prolonged working in excessive heat and humidity can render the skin more prone to infection.

4. What can be done to reduce the risks?

Dermatitis is more easily prevented than cured. Preventive measures fall into three main groups:
 

• Environmental protection: This means replacing the hazardous substance by something that does not have the potential to cause skin irritation. However, as you are more likely to find hazardous substances on a trader’s premises, this will generally not be possible. Ventilation or dust extraction equipment may also help.
• Personal protection: Safety clothing (e.g. gloves and barrier creams) can reduce skin contact with irritants, but it is better to protect both the skin and clothing likely to come into contact with the substance. This is because contaminated clothing which touches the skin causes prolonged exposure to the substance, making the effects much worse. Friction from clothing (e.g. at the collar, cuffs or waistband) can rub the irritant into the skin where it soaks through. Dusts can also penetrate clothing and mix with perspiration, allowing them to irritate the skin. This usually only occurs in parts of the body which are particularly prone to perspiration, such as the neck, armpits and groin.
• Cleanliness after exposure: This means washing hands and other exposed skin or showering if necessary. Ensuring remaining products are washed or removed from clothing and PPE.

You must refer to the legislation and the guidance of your national administration for more information. 
The guidance contained in this section intended to serve as a general reminder of the risks that are sometimes encountered during the examination and sampling procedure and of the safety equipment that you should use and precautions that you should take.