How is COSHH risk rating calculated?

Risk rating (Low, Medium, or High) combines hazard severity (GHS classification of the substance) with exposure likelihood (frequency, quantity, workplace controls). Our generator calculates this automatically based on your answers.

What is the hierarchy of control under COSHH 2002?

The hierarchy of control, in order: 1. Eliminate the substance. 2. Substitute with less hazardous alternative. 3. Engineering controls (ventilation, extraction). 4. Administrative controls (training, procedures). 5. PPE (last resort). Jumping straight to PPE without considering higher-level controls is a common COSHH failure.

What are common COSHH risk assessment failures in UK small businesses?

Common failures: using a generic template not specific to the workplace; same risk rating for all substances; jumping to PPE without considering ventilation; assessments never reviewed after 12 months; no sign-off from a competent person; emergency procedures copy-pasted from a different substance.

COSHH Risk Assessment Template UK, Risk Ratings Explained

How COSHH risk ratings actually work

Every COSHH risk assessment ends with a rating: Low, Medium, or High. This isn't arbitrary. Under HSE guidance, the rating is a combination of two things:

Hazard severity, the intrinsic danger of the substance based on GHS classification (e.g. Skin Corr. 1B vs Skin Irrit. 2)
Exposure likelihood, how often and how much the substance is used in your workplace, and what controls are already in place

LOW

Substance is a mild irritant or the exposure is very limited. Standard PPE and basic controls sufficient.

Example: acetone (nail polish remover) used occasionally in a well-ventilated salon.

MEDIUM

Substance is corrosive or irritant with daily/weekly exposure. Requires specific PPE, ventilation, and monitoring.

Example: sodium hypochlorite (bleach) used daily for surface disinfection.

HIGH

Substance is highly corrosive, toxic, or a sensitiser. Requires strict controls, monitoring, and formal training.

Example: sodium hydroxide (caustic oven cleaner) or PPD (hair dye).

The hierarchy of control, required by law

Under COSHH 2002, employers must apply the "hierarchy of control", you can't just skip to PPE. The hierarchy, in order of preference:

Eliminate, stop using the substance if possible
Substitute, swap for a less hazardous alternative (e.g. citric acid descaler instead of hydrochloric acid)
Engineering controls, ventilation, extraction, enclosed processes
Administrative controls, training, procedures, exposure time limits
PPE, gloves, goggles, respirators, the last resort, not the first

A common failure in Word-template risk assessments: jumping straight to "wear gloves" without considering substitution or engineering controls. Our COSHH risk assessment template guides you through this hierarchy for each substance.

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Automatic Low/Medium/High calculation based on your inputs. Edit the rating if a competent person disagrees.

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Common UK COSHH risk assessment failures

Based on published HSE inspection findings, these are the most common gaps in UK small business COSHH paperwork:

Assessment done at generic level, not specific to how the substance is actually used in the workplace, so failing the "suitable and sufficient" test required under Regulation 6
Same risk rating applied to all substances regardless of hazard class or actual occupational exposure
PPE listed without engineering controls (violating the hierarchy of control)
Not cross-referenced against the product Safety Data Sheet (SDS), which is the manufacturer's authoritative source for hazard information
Controls not reduced to as low as reasonably practicable, the legal wording that applies to all COSHH controls
Assessment never reviewed after 12 months (COSHH 2002 requires annual review)
No sign-off from a named competent person
No health surveillance programme for staff exposed to sensitisers, isocyanates, or other substances listed in Regulation 10
Emergency procedures missing or copy-pasted from a different substance