COSHH assessments for contractors

What COSHH covers

COSHH covers substances that can harm health when they are breathed in, swallowed, or in contact with the skin or eyes. That includes products bought in, such as adhesives, paints and cleaning chemicals, and substances the work itself creates, such as silica dust from cutting concrete, wood dust from sanding and fume from welding.

Some hazards sit under other regulations instead. Asbestos has the Control of Asbestos Regulations 2012, and lead has the Control of Lead at Work Regulations 2002. Substances that are dangerous only because they are flammable, explosive, radioactive, very hot or cold, or under high pressure are also outside COSHH, and the fire and explosion risks of flammable products are dealt with under the Dangerous Substances and Explosive Atmospheres Regulations 2002.

• Products classified as toxic, harmful, corrosive, irritant or sensitising
• Substances with a workplace exposure limit listed in HSE's EH40
• Biological agents, such as bacteria in sewage and contaminated water
• Dust of any kind at or above the concentrations set in the Regulations
• Fume and vapour given off by the work, such as welding fume and solvent vapour

What the assessment must consider

Regulation 6 lists what a suitable and sufficient assessment takes into account. Working through the list for each substance or process is the simplest way to be sure nothing is missed.

• The hazardous properties of the substance
• The supplier's health information, including the safety data sheet
• The level, type and duration of exposure
• The circumstances of the work, including the amount of substance used
• Activities such as maintenance where exposure could be high
• Any relevant workplace exposure limit
• The effect of the control measures that will be used
• The results of health surveillance and exposure monitoring, where they exist
• The combined risk where more than one substance is used together

The order of controls

Regulation 7 requires exposure to be prevented where reasonably practicable, and where it cannot be, adequately controlled using measures in a fixed order of priority. The assessment should show why each earlier option was not enough before relying on the next.

1. 1Prevent exposure: use a less hazardous product or method, such as water-based instead of solvent-based products, pre-cut materials, or fixing methods that avoid chasing and drilling.
2. 2Control it through the work process and equipment: on-tool extraction, water suppression, enclosed or wet cutting, and methods that produce less dust or fume.
3. 3Control it at source with ventilation: local exhaust ventilation for welding and other fixed processes, and ventilation of enclosed spaces.
4. 4Reduce who is exposed and for how long: exclusion zones, shorter tasks, cleaning up with a vacuum rather than a brush.
5. 5Add personal protective equipment last: respiratory protection matched to the substance and task, gloves suited to the chemical, eye protection. Tight-fitting masks need a face-fit test and a clean-shaven seal to work.

The substances contractors meet most

Most COSHH assessments on construction and maintenance jobs deal with the same handful of substances.

How a COSHH assessment fits a RAMS

The RAMS for the job names each hazardous substance as a hazard, summarises the controls and refers to the COSHH assessment for the detail. The COSHH assessment is attached to the RAMS or supplied with it, and the safety data sheets are kept available on site. The operatives are briefed on both.

Principal contractors often ask for the COSHH assessments with the RAMS, particularly for dust-producing work, spraying and anything used in an occupied building. A RAMS that says "wear appropriate PPE" for dust with no assessment behind it is one of the most common reasons a document is sent back.

Engineering controls have to be kept working. Local exhaust ventilation must be thoroughly examined and tested at least once every 14 months, and non-disposable respiratory protection must be examined and tested at suitable intervals.

Common mistakes

These are the gaps a reviewer or an HSE inspector usually finds.

• Safety data sheets filed as if they were the assessment
• One generic assessment for "chemicals" covering every product on the van
• No assessment at all for dust or fume the work creates
• Dry cutting or sweeping, with a disposable mask as the only control
• Tight-fitting respiratory protection with no face-fit test, or worn over stubble
• Health surveillance not arranged where the work needs it
• Assessments not reviewed after a change of product, method or site

Questions

Sources

The legislation and HSE guidance this guide is based on. Legislation links go to the revised text on legislation.gov.uk.

1. The Control of Substances Hazardous to Health Regulations 2002 · legislation.gov.uk
2. COSHH 2002, regulation 6 (assessment of the risk to health) · legislation.gov.uk
3. COSHH 2002, regulation 7 (prevention or control of exposure) · legislation.gov.uk
4. COSHH 2002, regulation 9 (maintenance, examination and testing of control measures) · legislation.gov.uk
5. Working with substances hazardous to health: a brief guide to COSHH (INDG136) · Health and Safety Executive
6. EH40/2005 Workplace exposure limits · Health and Safety Executive
7. Construction: hazardous substances · Health and Safety Executive
8. Construction: silica dust · Health and Safety Executive
9. Controlling airborne contaminants at work: a guide to local exhaust ventilation (HSG258) · Health and Safety Executive