Health and Safety Executive

return to source document

Appendix(para 2)- Risk Matrix : Chemical Agents

1
Topic		 2 Descriptor 3
Application/ Interpretation		 4 Likelihood Notes
Probable Possible Remote Nil/Negligible
Carcinogens, (EH40 Appendix 5), mutagens and substances toxic to reproduction. SERIOUS HEALTH EFFECT Potentially fatal, progressive etc. Where the risk of cancer is so high that the majority of people will be affected. This is very unlikely in the occupational context. Repeated or prolonged exposure. In some cases occasional exposure. (This is dependent on potency.) Single or very occasional exposure. Exposure above the exposure limit or above the reasonably practicable level for a substance with an MEL. Exposure at or below the OEL including the MEL requirements of ALARP. BENCHMARK Exposure in this context means actual or potential exposure at any exposure limit that may be set. The application was selected on the basis of potential outcome and lesser possibilities can be discounted.
Acute lethal agents SERIOUS HEALTH EFFECT By definition the outcome can be fatal. Gross exposure, for example, gases in confined spaces or large spills from a major incident, or extensive skin contact with phenol. Gross exposure. (As for 'probable'. It is not possible to generally distinguish these.) Single exposure above the exposure limit. No exposure or exposure to or below any exposure limit. BENCHMARK Exposure in this context means actual or potential exposure at a set exposure limit. Gross exposure means many times over the exposure limit, or gross skin contamination.It would be necessary to consider the toxicity of individual substances to define this closer but likely to be in the order of 10x the limit.
Respiratory sensitisers SERIOUS HEALTH EFFECT Leading to a person being sensitised to a substance and suffering occupational asthma. Repeated and prolonged exposure to highly potent sensitisers such as some platinum salts, MDI and TDI. Repeated and prolonged exposure to other asthmagens. Single or very occasional exposures above exposure limits. Exposure at, or below, any exposure limit including any MEL requirement. BENCHMARK This is not applicable to sensitised persons when a single exposure, even to very small levels, can lead to a probability of harm. It is likely then that the only remedy is removal of the individual from the risk of any exposure.
Corrosives SERIOUS HEALTH EFFECT Likely to cause permanent damage, eg exposure to the eyes. Or there is a progressive effect, eg HF. Actual contact with corrosive substance. Risk of contact but the duration limited by readily available remedial measures. Not likely to be applicable as the risk of injury is considered to be either 'possible' or if no exposure potential 'NIL'. BENCHMARK There may be more severe or less severe outcomes than described dependent on extent of contact ranging from a minor splash to immersion.
SIGNIFICANT HEALTH EFFECT Non-progressive but with a temporary or cosmetic disability Actual contact with 'severe burns' corrosive substance. Extended exposure to a substance causing 'burns'. Short-term exposure to substances causing 'burns'. BENCHMARK
Substances causing dermatitis SERIOUS HEALTH EFFECT Allergic contact dermatitis involving sensitisation. Continuous or frequently repeated skin contact with a dermatitic agent, eg R43 substance. Occasional contact. Single contact BENCHMARK
SIGNIFICANT HEALTH EFFECT Occupational dermatitis. Non-progressive and usually temporary disability. Continuous or frequently repeated skin contact with a dermatitic agent, eg R43 substance. Occasional but substantial contact. Occasional contact. Single contact BENCHMARK Occasional contact ranges from intermittent tasks to potential failings in protective clothing. Single contact is unlikely to result in the condition and tolerance of this is implicit in the benchmark.
Irritants SIGNIFICANT HEALTH EFFECT Non-permanent disability. Repeated & prolonged gross exposure. Repeated & prolonged exposure. Single exposure. BENCHMARK
General view of chemicals that do not lead to the above outcomes. SERIOUS HEALTH EFFECT For chemicals where the toxicology shows a serious end health effect. Examples in OC 130/5 Appendix 1 Gross exposure. Exposure to multiples of the exposure limit. Exposure above the exposure limit. (See reference to MELs in 'Notes' column). Below exposure limits. BENCHMARK Exposure limits means OEL including short-term limits and mixed exposures. It includes exposure as far as is reasonably practicable below the MEL. The term 'multiple' means several times (2-3) and 'Gross' means greater than this.
This is a generalisation and the health effects from the specific substance must be considered before making enforcement decisions.
SIGNIFICANT HEALTH EFFECT For chemicals where there is a less serious outcome. Examples in OC 130/5 Appendix 2 As above As above As above As above BENCHMARK

Quick links

Directgov - Business Link

Updated 01.06.09