Diesel Engine Exhaust Emissions (DEEEs)

Risk Assessment

Health and safety regulations require employers to carry out an assessment of the risks to the health from hazardous substances present in the workplace. A suitable and sufficient risk assessment is required wherever exposure to diesel engine exhaust emissions (DEEEs) is likely to occur.

Where there are five or more employees a written copy of the risk assessment should be provided and employees should always be informed of any significant findings from the assessment process.

Understanding when employees and others may be exposed to diesel exhaust emissions is important when conducting a risk assessment.

In workplaces, the following factors contribute to the quantity and composition of DEEEs:

the type of engine, e.g. non-turbocharged, turbocharged diesel engine
whether the engine has been regularly maintained and tuned
the specification of the fuel used
the workload demand on the engine, e.g. whether the engine is required to work near its capacity
the engine temperature, e.g. starting from cold
number of vehicles running at any one time

A number of factors may be considered when assessing the level of risk associated with DEEEs in a workplace. For example, if there is obvious blue or black smoke in the workplace that is present on a regular basis the risk is likely to be high. The extent of soot deposits throughout the work area is also a good indication of the level of risk, as is the number of complaints of irritancy by workers.

In general terms, blue smoke indicates a poorly serviced and/or tuned engine whilst black smoke indicates a mechanical fault with an engine. White smoke (water droplets and unburnt fuel) is produced when engines are started from cold and disappears when the engine warms up.

In assessing the level of risk from DEEEs the following series of questions should be asked:

How likely is it that exposure to DEEEs will happen?
Who could be affected, to what extent and for how long?
How many people are potentially exposed to DEEEs?
How can exposures be avoided?

In some circumstances, the assessment may necessitate carrying out monitoring to assess the effectiveness of any controls.

Further information on DEEEs are available within the following HSE publications:

An example risk assessment for a motor vehicle repair workshop shows the kind of approach a small business might take when considering diesel exhaust as an occupational health hazard.

This template should be used only as a guide to completing a risk assessment. As every business is different, employers should carefully think through the hazards and controls unique to their work activity.

Further information on how to conduct a risk assessment is available within the HSE publication A step by step guide to COSHH assessment.

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