COSHH frequently asked questions

COSHH assessment

I have just completed COSHH essentials, is this sufficient to use as my COSHH assessment?

COSHH essentials produces generic advice. The legal requirement is that the risk assessment must be suitable and sufficient, so check that the downloaded sheets fully describe the task you do. If so, follow the advice in the sheets. Otherwise, think about how else you could use the advice to avoid workers health being harmed. You should take into account any information you have on levels of exposure, such as the results of monitoring, or health checks.

For further information see the HSE publication A step by step guide to COSHH assessment.

Does my employer have to provide me with a copy of the COSHH assessment?

Employers must provide information about the hazards, risks and control measures, and instruction and training to use the control measures. All employers must carry out a risk assessment and those employing five or more employees must also record significant findings. This record needs to be accessible so that safety representatives, inspectors, etc. can examine it.

You can find further information on working with hazardous substances in the HSE publication Working with substances hazardous to health.

How do I carry out a COSHH risk assessment?

You should:

Gather information about the hazardous properties of the substances, the work, and the working practices (or find out what the problems are)

  • Evaluate the risks to health
  • Decide on the necessary measures to comply with Regulations 7-13 of COSHH
  • Record the assessment (if you have 5 or more employees)
  • Decide when the assessment needs to be reviewed

How often should I review a COSHH assessment?

An assessment should be revisited to ensure that it is kept up to date and an employer should do this regularly. The date of the first review and the length of time between successive reviews will depend on type of risk, the work, and the employers judgement on the likelihood of changes occurring.

The assessment should be reviewed immediately if:

There is any reason to suppose that the original assessment is no longer valid, eg evidence from the results of examining and testing engineering controls, reports from supervisors about defects in control systems; or

Any of the circumstances of the work should change significantly and especially one which may have affected employees exposure to a hazardous substance

The requirement is for a review of the assessment. This does not mean that the whole assessment process will have to be repeated at each review. The first purpose of review is to see if the existing assessment is still suitable and sufficient.  If it is, then you do not need to do any more.

If it appears that the assessment is no longer valid, it does not mean that the whole assessment has to be revised.  Only those parts that do not reflect the new situation need amending.

Whether or not there is any real change in the situation, there is an absolute requirement to review the situation on a regular basis. Without this, there is a danger that gradual change over a period of time goes unnoticed and the assessment becomes unsuitable and insufficient by default.

For further information about COSHH assessment is available in the HSE publication A step by step guide to COSHH assessment.

How do I carry out a COSHH assessment for a substance that does not have a Safety Data Sheet, for example dust?

Some substances are process generated, for example wood dust released from sawing wood. Employers should regard a substance as hazardous to health if it is hazardous in the form in which it occurs in the work activity. You should find out if there are any health effects associated with working with the hazardous materials identified and look at how workers could be exposed, for example do you use a dry brush to sweep up dust? Use this information to evaluate risks to health and minimise exposure by taking sensible measures, such as using a vacuum cleaner instead of a brush, or keeping lids on containers. How do I carry out a COSHH risk assessment? provides more information.

Safety data sheets

How do I get safety data sheets and how do I use them?

If a substance is dangerous for supply, the supplier must send you a data sheet when the product is first ordered, if the formulation changes, or if you ask for a sheet. If it is not dangerous for supply the supplier should include instructions for safe use with the package. Report suppliers who refuse to provide safety information to HSE.
The parts of a safety data sheet you may find most useful are:

Further information on Safety data sheets is available.

We have the Safety Data Sheets for all of our hazardous substances; do we still need to carry out COSHH risk assessments?

YES. A good safety data sheet (SDS) does not substitute for carrying out and recording a COSHH risk assessment.  Gathering SDSs is only the first stage in the assessment process. The SDS will provide information on the hazardous properties of the substances you are using, any health effects associated with its use, how likely it is to get into the air or onto the skin, and what risk reduction measures you should use to control exposure to an acceptable level. However, it will not be specific to your workplace and cannot take into account the particular environment you work in. Working with substances hazardous to health provides more information

Keeping records

What needs to be included in a record of health surveillance?


  • The persons name and National Insurance number
  • The substance they are exposed to, and when (start date, frequency of use)
  • The surveillance test that is done on them, and the tester
  • The outcome e.g. passed / retest / failed (but not the test data).

Remember that a Health Surveillance record is different to a medical record.

Medical records are generated by a health professional, namely a Dr or Nurse, who is competent as regards the hazard, risks and likely health effects. The information contained in a Medical Record depends on the nature of the medical carried out. ALSO the Medical Record is medical-in-confidence material and it is the responsibility of the health professional that has created it to ensure that nobody else gets access without informed consent from the individual whose medical record it is.

Further information on health surveillance overview is available.

What do I do with medical records if my company is going out if business?

They can be offered to HSE Employment Medical Advisory Service personnel locally. Alternatively it can be given to the employee/patient or, with their consent, give it to their GP, as information that may be useful in future.

Do we need to record COSHH assessments on a specific form?

No. Risk assessments may vary in their complexity, so you are free to use something that works for you. However, make sure you cover the key points:

  • what are the dangers, and to whom, doing what task
  • what control measures could prevent harm
  • using these control measures and checking that they work

Further information on risk assessments in particular industries is available.

Working with hazardous substances

What is a substance hazardous to health?

A substance hazardous to health is a substance or mixture with the potential to cause harm if they are inhaled, ingested, or come into contact, or are absorbed through the skin

The COSHH Regulations apply to any substance:

a) which is listed in Table 3.2 of part 3 Annex VI of the CLP Regulation and for which an indication of danger specified for the substance is very toxic, toxic, harmful, corrosive or irritant;

b) for which the Health and Safety Executive has approved a Workplace Exposure Limit

c) Which is a biological agent

d) Which is dust of any kind, except dust which is a substance within paragraph (a) or (b) above, when present at a concentration in air equal to or greater than

10 mg/m3 as a time weighted average over an 8 hour period of inhalable dust or

4mg/m3 as a time weighted average over an 8 hour period of respirable dust

e) Which, not being a substance falling within sub-paragraphs (a) to (d), because of its chemical or toxicological properties and the way it is used or is present at the workplace creates a risk to health

Do the cleaning chemicals have to be kept in a locked cupboard?

Locking up cleaning chemicals is sensible if vulnerable people such as children or learning-impaired persons are able to gain access to them.

I work with chemicals, but the employer has no procedures in place to control the exposure to them. What can I do?

Report the matter to HSE's Concerns and Advice Team or Local Authority Environmental Health Officer. You can do so anonymously.

What are the ventilation requirements when working with hazardous substances, what do the regulations require etc

Ventilation of the building – you need good general ventilation, which normally means five to 10 air-changes per hour - talk to a heating and ventilation engineer.

Ventilation of a process, usually called local exhaust ventilation (LEV) means extracting any gas, vapour, fume, mist or gas from a source of airborne contaminant. The rate of extraction depends on the size of the source. The shape of the hood that collects the contaminant cloud depends on the speed and direction of the contaminant cloud. You need to talk to a competent person. See:

See HSE's local exhaust ventilation website

Don't forget that ventilation has little effect on exposure of, or through, the skin


What training / qualifications should I have to carry out COSHH assessments?

You don't need any particular qualifications but you must be competent. This means you must have the necessary knowledge, skills and experience to do the job properly. You should:

  • understand hazard and risk
  • know how the work can expose people to substances hazardous to health
  • have the ability (and authority) to collect all the necessary information
  • have the knowledge, skills and experience to make the right decisions about how to control exposure.

Look at the HSE website for advice about your trade under Your Industry, or under COSHH Health & Safety Topics. If you are a member of a Trade Association, ask them for help.

Training courses are now available from training providers and you can get further details directly from the from the further information part of this site.

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