COSHH Assessment

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  • Hazard identification and assessment for products.
  • Implementing exposure scenarios in the workplace.
  • COSHH assessment.
  • Advice on risk management.

Risk assessment

The Control of Substances Hazardous to Health (COSHH) Regulations implement the EU Chemical Agents Directive 98/24/EC.

The legislation requires that employers make a risk assessment for hazardous chemicals in the workplace.

All chemical substances may be used safely, even if they are highly hazardous, provided that exposure of workers can be maintained below acceptable limits. This principle thus differentiates between risk, and hazard, as follows:

Risk = Hazard × Exposure

This equation gives a useful qualitative appreciation of how risk can be managed through an understanding of hazards (eg skin irritation, carcinogenicity) of a product, and how workers come into contact with it (exposure).

Information for COSHH assessment

For chemical products, the employer can source information for the COSHH assessment from the safety data sheet (SDS) and the Chemical Safety Assessment (CSA), which gives generic information on:

  • Hazards, eg flammability, irritation, carcinogenicity
  • Physico-chemical properties, eg dustiness, volatility that affect spread of the product in the workplace
  • Routes of exposure, eg inhalation, skin absorption
  • Exposure limits, such as UK Workplace Exposure Limits (listed in HSE publication EH40/2005) and the derived-no-effect levels (DNELs) in the CSA
  • Recommended operating conditions and risk management measures
  • Emergency procedures, first-aid and spills
  • Disposal procedures

The employer should receive an SDS from their supplier for any product that is either: (a) classified as hazardous according to the CLP Regulation (1272/2008); or (b) contains a substance with an EU exposure limit value.

For hazardous substances supplied at >10 tonnes per year in the EU, a comprehensive risk assessment is required as part of the REACH Registration dossier, ie the Chemical Safety Assessment (CSA).

For each route of exposure, the CSA gives derived-no-effect levels (DNELs) which are considered safe for the stated exposure period (long- or short-term).

The CSA also contains exposure scenarios (ESs) for each activity (eg pouring, mixing, spraying) in the life cycle of the product. The ESs give recommended risk management measures (RMMs) that adequately control exposure to safe levels if implemented in the workplace.

The manufacturer or importer should be append the ESs to the SDS as an Annex giving the extended safety data sheet, so that the downstream user can implement suitable RMMs in the workplace.

COSHH assessment

COSHH assessment focuses on practical measures that the employers take in the particular workplace to control the potential harm to workers.

The author of the COSHH assessment adapts the generic information from the SDS and CSA to the specific workplace with information regarding:

  • Specific tasks that workers undertake while using the product (eg pouring, mixing, maintenance)
  • Training and supervision of staff for the specific tasks, including correct use of personal protective equipment (PPE)
  • Installation and maintenance of any engineering controls, such as ventilation
  • Exposure reduction through work practices, eg reducing number of exposed workers, reducing time of exposure, separation of substance and worker by time or distance.
  • Provision and maintenance of PPE
  • Monitoring of worker exposure
  • Emergency procedures, first-aid points, clean-up kits
  • Record keeping for training, procedures, monitoring, adverse effects, and review of the assessment.

The COSHH assessment should be proportionate to the risk. It is often straightforward to assess, for example, the use of small amounts of hazardous cleaning products in the workplace. For use of highly hazardous products in large amounts, the COSHH assessment is more rigorous.

Employers are tasked with preventing exposure and minimising the risk. The employer should reduce exposure, balancing the risk presented by the substance, compared to the cost and effort of further risk reduction measures. In all cases the exposure should be below occupational limits.

For some hazardous properties, particularly carcinogenicity, mutagenicity, and respiratory sensitisation, it is not always possible to derive safe levels. For substances with these properties, worker exposure should be reduced to as low as reasonably practicable. This usually mean containing them in a closed system.