Chemicals & the skin

We all handle chemicals, even though we sometimes do not recognise this. How many of us have skin contact with dihydrogen monoxide, i.e. water, on a daily basis? Do we consider this an issue? Yet ‘wet work’ is the most common cause of occupational contact dermatitis and water has been recognised for many years by dermatologists as a skin irritant. It is all a question of balance. With many chemicals skin contact up to a certain point can be beneficial, thereafter it can result in damage. Where this point lies is often impossible to determine with any certainty.

CLP & COSHH regulations

Sometimes the attitude we encounter is that skin damage is not that serious, but only a rash. If this is the case, why is there a Hazard Statement under the new CLP Regulations of H310 – Fatal in contact with the skin? The Control of Substances Hazardous to Health (COSHH) regulations recognise this. COSHH requires us to adequately control exposure to a substance hazardous to health. It defines a substance hazardous to health in a number of ways, including:

"(e) which, not being a substance falling within sub-paragraphs (a) to (d), because of its chemical or toxicological properties and the way it is used or is present at the workplace creates a risk to health” (Regulation 2[1])

According to this any substance can become a substance hazardous to health. This is correct as even water, under certain circumstances, can be hazardous to the skin, particularly when combined with a skin cleanser. This raises an important issue, that of the real hazard when we use chemicals. We usually purchase chemicals to use for a particular purpose. In the process it is highly probable that we will change their properties and thus the hazard that is present.

A simple example could be using a floor cleaning chemical. This is placed in the tank of the scrubber-drier and diluted with water. Already the data on the safety data sheet may no longer be correct, since diluted there is probably a reduction in the hazard. We then apply the chemical to the floor, then recover this, combined with the soiling removed from the floor. In the waste water tank we now have a mixture of the cleaning chemical, water and whatever has been recovered from the floor, possibly with a number of unknown hazards! 

The sixth edition of ACoP for COSHH recognises this. Paragraph 35 states:

When deciding whether the substances used or produced in the workplace are covered by COSHH, employers should also consider the following: 

• Different forms of a substance may present different hazards, e.g. substances may not be hazardous in solid form but may be hazardous when ground into fine powder or dust that can be breathed into the lungs. 

• Nanoparticles (i.e. particles less than 100 nanometers) may be more toxic than larger particles of the same chemical substance. 

• Impurities in a substance can make it more hazardous, e.g. crystalline silica is often present in minerals which would otherwise present little or no hazard. 

• Some substances have a fibrous form which may present a potentially serious risk to health if the fibres are of a certain size or shape. 

• Some substances have a known health effect but the mechanism causing it is unknown, e.g. certain dusts of textile raw materials cause byssinosis. 

• Exposure to two or more substances at the same time or one after the other may have an added or synergistic effect. 

• Epidemiological or other data, e.g. reports of illness due to new and emerging agents, indicate that a biological agent that does not already appear in The Approved List of biological agents could nevertheless cause a hazard to health. 

• One-off, emergency situations arising out of the work activity, such as a dangerous chemical reaction or fire, could foreseeably produce a substance hazardous to health.

Deciding exactly what hazard we need to base our risk assessment on can often be complex and may require specialist expertise. It is arguably the most difficult part of most COSHH risk assessments, particularly for skin exposure. Simply basing the risk assessment on the package labelling or safety data sheet can frequently result in an invalid risk assessment and be putting worker health at considerable risk.