A COSHH assessment under the Control of Substances Hazardous to Health Regulations 2002 (as amended) is required for any substance hazardous to health used at work — adhesives, solvents, paints, cement (silica is the main UK construction COSHH driver), MDI in insulation, oils, dusts, fumes from cutting and welding. The assessment is product-specific and task-specific; a single COSHH for 'all site chemicals' is non-compliant on its face.
COSHH 2002 (SI 2002/2677) applies to any substance hazardous to health — which includes substances with a CLP hazard classification, substances with a Workplace Exposure Limit (WEL) listed in HSE EH40, biological agents, and substances generated by the work itself (welding fume, RCS / respirable crystalline silica from cutting concrete or stone, wood dust). The last category catches contractors who think COSHH only applies to bottles with hazard labels — the cement dust from a road saw or the silica from a stone bench-saw is in scope.
The assessment is required by regulation 6 before the substance is used. 'Suitable and sufficient' is the statutory test — it has to be a real evaluation of this substance in this task by these people, not a copy of the safety data sheet.
Regulation 7(1) requires exposure to be prevented or, where not reasonably practicable, adequately controlled. The hierarchy is: eliminate the substance, substitute with a less hazardous one, engineering controls (LEV — local exhaust ventilation, water suppression on saws, enclosure), then ways of working, then PPE / RPE as the last resort. A COSHH assessment that goes straight to dust mask + nitrile gloves without addressing the hierarchy is non-compliant.
For silica work this is the single most-cited deficiency by HSE inspectors. The assessment must show that water suppression or on-tool extraction (M-class minimum, H-class for asbestos) was considered before RPE.
HSE EH40/2005 (most recent amendment 2025) lists the Workplace Exposure Limits — long-term (8-hour TWA) and short-term (15-minute STEL). Respirable crystalline silica sits at 0.1 mg/m3 (8-hour TWA), wood dust (hardwood) at 3 mg/m3, MDI at 0.005 mg/m3. The assessment quotes the WEL for the substance, the estimated exposure level, and the controls that bring exposure below the WEL.
Where RPE is required, the assessment names the RPE (e.g. FFP3 disposable, half-mask with P3 cartridge, powered respirator TH3), the assigned protection factor (APF), and the face-fit testing regime — face-fit is required for tight-fitting RPE under HSE OC282/28.
Where the COSHH assessment concludes there is a residual risk to health, regulation 11 requires health surveillance — typically annual lung-function testing (spirometry) for RCS / wood dust / welding fume exposure, skin checks for solvent / wet cement exposure, and biological monitoring for lead. The assessment names the surveillance regime, the provider (typically an OH service), and the recall interval. Failure to put surveillance in place is one of the highest-frequency HSE COSHH improvement notices issued each year.
The numbered sections a reviewer expects to see, in order.
Product name, manufacturer, CAS / EC number, the specific task in which it is used, frequency and duration.
CLP hazard classification, GHS pictograms, hazard statements (H-codes), reference to safety data sheet section 2.
Long-term and short-term WELs; how the estimated exposure compares.
Eliminate / substitute / engineering / ways of working / PPE — applied in order with justifications for skipping any tier.
LEV, water suppression, on-tool extraction (M-class or H-class), enclosure — specification and TExT inspection interval.
Glove material (per EN 374 permeation), eye protection (EN 166), RPE model with assigned protection factor and face-fit record.
Spill response, first-aid measures (eye-wash station, skin decontamination), emergency contact.
Surveillance regime (spirometry, skin checks, biological monitoring), provider, recall interval.
Operatives briefed on the assessment, SDS available, training records dated.
Why a coshh assessment gets sent back — these are the patterns we see most often.
The legal framework this coshh assessment operates inside. Links go to the official source.
SI 2002/2677
The statutory framework — assessment duty, hierarchy of control, health surveillance.
HSE EH40
The reference document for UK WELs — quoted in every defensible COSHH assessment.
HSE L5
Approved Code of Practice with statutory weight — the benchmark reviewers use.
HSE INDG136
Plain-English summary of COSHH duties for employers and contractors.
Yes. Wet cement is a skin and eye irritant (CLP H315, H319) and a Category 1 skin sensitiser (H317) at chromium-VI levels. Dry cement dust contains respirable crystalline silica (RCS) above the EH40 WEL when cut or mixed dry. Both wet-handling and dust generation tasks require a COSHH assessment.
No. The SDS describes the substance; the COSHH assessment evaluates how *this substance is used in this task by these people on this site*. HSE inspectors routinely reject SDSs presented as COSHH assessments — the assessment has to add the task-specific exposure analysis and the chosen controls.
Yes where the COSHH assessment shows residual exposure to RCS. Standard surveillance is annual lung-function testing (spirometry) by a competent OH provider, with a baseline at first exposure. Failure to implement this is a regulation 11 breach and one of the most common HSE improvement notices in construction.
Whenever the work, the substance, the controls or the people change, and in any case 'at suitable intervals' under regulation 6(3). Most UK contractors review annually as a minimum and re-issue per project where the substances or method change.
The WEL is the long-term (8-hour time-weighted average) limit. The STEL is the short-term (15-minute) limit. Both are published in HSE EH40. A COSHH assessment that controls below the long-term WEL but allows brief excursions above the STEL is still non-compliant.
Trade-specific RAMS guidance for the contractors who typically produce this coshh assessment.
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Final RAMS must be reviewed and approved by a competent person before use.