Adequate Control Under COSHH: What the Hazard Statement Demands

Classification is a property of the substance. Risk is a property of your work.

That sentence is easy to agree with and hard to operationalise. A Safety Data Sheet tells you a substance can cause cancer, or sensitise the airways, or corrode skin. It cannot tell you how much of it your people breathe on a Tuesday, how long the task runs, or whether the extraction installed six years ago still moves the volume it was commissioned for.

Bridging that gap is what the COSHH Assessment does. The hazard classification a substance carries decides which duties land on you in the first place. This is the step after that, when a hazard statement in front of you has to become a control decision you can defend.

What Regulation 6 asks for

Most people describe the COSHH Assessment duty as a requirement to assess risks. Regulation 6 sets a higher bar than that.

An employer must not carry out work liable to expose employees to a substance hazardous to health unless two things have happened. A suitable and sufficient assessment has been made, and the steps it identifies have been implemented.

Those two limbs sit at Regulation 6(1)(a) and 6(1)(b). An assessment sitting in a folder while the controls it specifies are still on order satisfies the first and breaches the second.

The list nobody reads

Regulation 6(2) then sets out what the assessment must consider, and the list runs wider than a typical COSHH Assessment template.

It covers the hazardous properties of the substance, the health effects information supplied with it including anything in the Safety Data Sheet, and the level, type and duration of exposure. It also covers the circumstances of the work including the amount involved, activities such as maintenance where there is potential for high exposure, and the risk presented where employees are exposed to more than one substance in combination.

Two of those catch people out.

Maintenance appears in the Regulation by name. Routine production is usually assessed carefully, while the filter change, the tank entry and the annual strip-down are handled by whoever happens to be on shift. Those are frequently the highest-exposure activities on site.

Combined exposure is the other. Assessments are written substance by substance, because that is how Safety Data Sheets arrive. Regulation 6(2) asks about the combination, which is a different question and rarely a documented one.

Prevention before control

Regulation 7 requires employers to prevent exposure to substances hazardous to health. Adequate control is the fallback, available only where prevention is not reasonably practicable.

Control is the easier half to document. Gloves, extraction, a training record. The prevention question, whether the substance needs to be there at all, or whether a less hazardous one would do the job, can go unrecorded even when it was genuinely considered.

That omission is worth fixing for a practical reason. An inspector asking why a Category 1B carcinogen remains in use wants to see the substitution reasoning. An assessment that never documents the question looks like one where nobody asked it.

Where control is the answer, the Health and Safety Executive (HSE) sets out eight principles of good control practice in Schedule 2A to the Regulations. They must all be applied, and HSE is explicit that they are not ranked, so the last carries the same weight as the first.

Where the hazard statement changes the standard

Here is the part that separates a compliant assessment from a generic one.

Regulation 7(7) defines adequate control through a three-part test. The Schedule 2A principles must be applied. Any approved workplace exposure limit must not be exceeded. And for certain substances, exposure must be reduced to as low a level as is reasonably practicable.

That third limb is triggered by the hazard statement itself. The Regulation names them.

Carcinogens and mutagens

Substances carrying H340, H350 or H350i fall into the higher standard, along with processes listed in Schedule 1 to the Regulations. Schedule 1 reaches processes that count as carcinogens without any classification, including hardwood dust and silica generated by a work process. Staying under a workplace exposure limit is no longer sufficient on its own. Exposure has to be pushed as low as reasonably practicable, which is an open-ended duty with no threshold to clear.

The expectation extends further than the classified substances. The Approved Code of Practice recommends an active precautionary policy of prevention and control for substances suspected of being carcinogenic, and that employers should have a system for identifying them. Suspicion is enough to engage it.

Respiratory sensitisers

H334 triggers the same higher standard, as does anything in section C of HSE's Asthmagen publication.

The reasoning behind that is worth understanding, because it changes how the assessment should read. Sensitisation is not a dose-response effect in the ordinary sense. Once a worker becomes sensitised, exposures that everyone else tolerates without difficulty can produce a serious reaction. Isocyanates in spray booths, flour and enzyme dusts in bakeries, colophony in soldering fume, laboratory animal proteins.

An assessment concluding that exposure sits comfortably below a limit has answered a question about the average worker. For a sensitiser, the individual is the unit that matters.

Substances with a workplace exposure limit

Where HSE has approved a workplace exposure limit, exceeding it means control is inadequate as a matter of law. The limits are published in EH40, HSE's list of workplace exposure limits, which is revised periodically.

The practical trap is treating the limit as a target. It sets a ceiling, and Schedule 2A still applies underneath it. A workplace holding exposure at ninety per cent of a limit while a reasonably practicable improvement sits unimplemented has a compliance problem despite the number looking acceptable.

When the class triggers health surveillance

Regulation 11 sets out when health surveillance is required. Schedule 6 pairs specific substances in one column with specific processes in another, and surveillance applies where an employee is exposed to a listed substance while engaged in the listed process. It applies more widely too, wherever the assessment shows an identifiable disease or adverse health effect may be related to the exposure and a valid technique exists for detecting it.

Where Schedule 6 bites, the requirement steps up again. Surveillance then has to include medical surveillance under a relevant doctor at intervals of no more than 12 months.

Which means the classification frequently supplies the first signal. A respiratory sensitiser in use points toward respiratory health surveillance. A substance causing dermatitis points toward skin checks by a suitably trained person at defined intervals.

Health records carry a retention period that surprises people. They must be kept for 40 years from the date of the last entry, reflecting how long occupational disease can take to appear. An organisation that changes system, or loses a filing cabinet in an office move, has created a problem that surfaces decades later.

Keeping the assessment current

A COSHH Assessment is built on inputs that move. When a supplier revises a classification after a change to the mandatory list, a substance can acquire a hazard statement that pulls it into the as-low-as-reasonably-practicable standard. Nothing on site changes. Every assessment referencing that substance is now written to the wrong test.

Catching that depends on knowing which assessments reference which substances, which is straightforward on one site and unmanageable across nine on spreadsheets.

That link is what Sevron built into Safety365. COSHH Assessments stay tied to the substances they cover and to the Safety Data Sheets behind them, so a supplier reclassification surfaces against everything it touches. The Accelerated Compliance framework wraps that in training and record-keeping, so being certified, competent and compliant becomes a position you hold continuously. For teams starting from scratch, the free five-step Risk Assessment wizard is a way to see the shape of a structured assessment without an account.

The classification tells you which test applies. The assessment is where you show you met it.

Frequently Asked Questions

What makes a substance hazardous for health under COSHH?

It meets the criteria for any health hazard class under the CLP Regulation, carries a workplace exposure limit approved by HSE, or is a biological agent or dust present in substantial airborne concentrations. The Regulations use the term substance hazardous to health, and the classification is usually the first signal that one applies.

Does a COSHH Assessment have to be written down?

Yes, where five or more people are employed. The significant findings must be recorded, and the assessment reviewed when it is no longer valid or when circumstances change.

What makes a COSHH Assessment "suitable and sufficient"?

It must cover everything Regulation 6(2) lists, including exposure levels and duration, maintenance activities, and combined exposure where more than one substance is involved. Generic assessments copied from a Safety Data Sheet rarely meet this.

Does meeting the workplace exposure limit mean control is adequate?

Not by itself. The Schedule 2A principles must also be applied, and substances carrying H340, H350, H350i or H334 must be reduced to as low a level as is reasonably practicable.

When is health surveillance required under COSHH?

Where Schedule 6 lists both the substance and the process an employee is engaged in, or where the risk assessment shows exposure is linked to an identifiable disease and a valid detection technique exists. Records run for 40 years from the last entry.

How often should a COSHH Assessment be reviewed?

There is no fixed interval in the Regulations. The trigger is validity, so a review is due when the substance, process, controls or classification change, or when health surveillance or monitoring suggests controls are underperforming.