A COSHH Assessment Form is a structured document used by employers to identify, evaluate, and record the risks to health arising from work involving substances hazardous to health, and to specify the control measures required to prevent or adequately control those risks. In England and Wales, the legal obligation to carry out COSHH assessments is established by the Control of Substances Hazardous to Health Regulations 2002 (SI 2002/2677), made under the Health and Safety at Work etc. Act 1974 (HSWA 1974, s.2).

The COSHH Regulations 2002 apply to a wide range of substances hazardous to health, including chemicals classified as toxic, harmful, irritant, corrosive, carcinogenic, mutagenic, or reprotoxic under the Classification, Labelling and Packaging Regulation (EC) 1272/2008 (retained EU law, known as the CLP Regulation); dusts of any kind when present at a concentration in air equal to or greater than the relevant Workplace Exposure Limit (WEL) listed in EH40; biological agents such as bacteria, viruses, fungi, and parasites; naturally occurring substances such as grain dust, wood dust, and rubber latex; and any substance for which a WEL has been assigned in EH40 Workplace Exposure Limits (4th edition, HSE, 2020).

Regulation 6 of the COSHH Regulations 2002 requires every employer to carry out a suitable and sufficient assessment of the risks created by work involving hazardous substances before that work commences, and to record that assessment in writing where there are five or more employees. The assessment must identify what substances are present or may be encountered, who may be harmed and how, what controls are already in place, and what further action is required. The assessment must be reviewed regularly and whenever there is reason to believe it is no longer valid — for instance following an accident or incident, a change to the work process, new scientific information, or a change in the workforce.

The COSHH assessment process is closely linked to other legal requirements under the COSHH Regulations 2002. Regulation 10 requires employers to monitor workplace exposure where it is necessary to ensure that WELs are not exceeded and that control measures are effective. Regulation 11 requires appropriate health surveillance for employees exposed to substances linked to occupational disease, such as occupational asthma, dermatitis, or bladder cancer. Regulation 12 requires employers to provide employees with sufficient information, instruction, and training about the substances they work with, the risks involved, and the precautions to be taken. Regulation 13 requires employers to establish emergency arrangements for dealing with accidents and incidents involving hazardous substances. Together, these provisions create a comprehensive framework for protecting workers from the health effects of hazardous substances, ranging from acute effects such as chemical burns and respiratory irritation to chronic diseases including occupational asthma, dermatitis, silicosis, mesothelioma, and occupational cancer.

The Health and Safety Executive (HSE) estimates that over 13,000 deaths each year in Great Britain are linked to past exposures at work, predominantly from lung disease and cancer. Many of these deaths are preventable through effective implementation of the COSHH Regulations. This COSHH Assessment Form provides a structured, legally compliant approach to recording all required information in one place, and is suitable for use by employers, health and safety officers, and safety representatives across manufacturing, laboratory science, construction, healthcare, cleaning and facilities management, agriculture, printing, hairdressing and beauty, automotive, and any other sector where workers may be exposed to hazardous substances.

A COSHH Assessment Form is legally required before any work commences that involves substances hazardous to health, and must be reviewed and updated regularly throughout the lifetime of the work activity. The requirement is broad in scope and applies across a very wide range of industries and job roles: laboratory scientists working with chemical reagents and solvents; cleaners using industrial detergents, disinfectants, and bleach; painters and decorators exposed to solvent fumes and isocyanates in spray paints; hairdressers working with hair colourants, bleach, and chemical straighteners; healthcare workers handling cytotoxic drugs, disinfectants, and glutaraldehyde; construction workers exposed to silica dust, cement dust, and wood dust; agricultural workers using pesticides and herbicides; automotive technicians working with engine oils, brake fluids, and solvent-based products; and printing workers exposed to inks, solvents, and adhesives.

A new or revised COSHH assessment is needed whenever a new substance is introduced into the workplace for the first time; when an existing substance is used in a new way, at a different concentration, in larger quantities, or in a different location or ventilation environment; when the number of persons exposed increases significantly or new groups of workers (including young persons, new or expectant mothers, or persons with pre-existing respiratory or skin conditions) begin work involving the substance; when the results of air monitoring or health surveillance indicate that existing controls are inadequate or that WELs may be exceeded; when there has been an accident, incident, near miss, or case of occupational ill health connected with the substance; when new scientific, toxicological, or epidemiological information about the substance becomes available, including updates to the EH40 WEL list or changes to the CLP hazard classification; or when the Safety Data Sheet is revised by the supplier.

From a regulatory enforcement perspective, the Health and Safety Executive routinely inspects workplaces across sectors where hazardous substances are used. An HSE inspector visiting a workplace may request to see COSHH assessments for any substances used on site. Failure to have a suitable and sufficient written COSHH assessment may result in the issue of a formal Improvement Notice under the HSWA 1974, requiring the employer to remedy the deficiency within a specified timescale, typically 21 days. More serious failures, particularly where employees have suffered harm or are at serious and imminent risk, may result in a Prohibition Notice requiring the work to stop immediately, or prosecution under the COSHH Regulations 2002 and the HSWA 1974. Convictions can result in unlimited fines and, in the most serious cases where directors or managers have been personally responsible for the failure, imprisonment.

COSHH assessments also serve important commercial and civil litigation purposes. A well-maintained set of COSHH assessments demonstrates an employer's due diligence and commitment to managing chemical health risks, which is required as a condition of many public sector procurement contracts and by employers' liability insurance underwriters. Insurers may impose higher premiums, exclusions, or additional excesses where an employer cannot demonstrate adequate COSHH compliance. In personal injury and occupational disease litigation, the COSHH assessment is frequently a key document in establishing whether the employer took all reasonably practicable steps to prevent harm. Under the Limitation Act 1980, occupational disease claims may be brought up to three years from the date of knowledge of the disease and its connection to work, meaning that COSHH records may be required as evidence in litigation many years after the relevant exposure occurred. Employers should therefore retain COSHH assessments and associated monitoring and health surveillance records for the periods prescribed by regulation and beyond.

A legally effective COSHH Assessment Form for use in England and Wales must address each stage of the assessment process mandated by the COSHH Regulations 2002. The form must be tailored to the specific substance, the specific task or activity in which it is used, and the specific workplace or work environment concerned. A generic or incomplete assessment is unlikely to be regarded as suitable and sufficient for the purposes of regulation 6.

The business and workplace details section establishes the context of the assessment, identifying the employer, the department or work area, and the person carrying out the assessment. The assessor must be a competent person — someone with sufficient training, experience, and knowledge of COSHH requirements and the substances being assessed. Assessor competence is a prerequisite for the validity of the assessment.

The substance identification section must provide enough detail to enable the substance to be unambiguously identified, including its chemical name, any synonyms or trade names, the CAS number where relevant, the manufacturer or supplier, and the Safety Data Sheet (SDS) version and date. The SDS is the primary technical reference for COSHH assessment purposes. Under UK REACH Regulation (the UK retained version of REACH Regulation (EC) 1907/2006), suppliers of hazardous substances are required to provide an SDS in accordance with Annex II of UK REACH whenever the substance or mixture meets the CLP criteria for classification as hazardous, and in certain other specified circumstances.

The hazard classification section translates the CLP classification of the substance into the relevant health risks. Acute toxicity classifications (categories 1 to 5) indicate the potential for harm from a single exposure. Skin and respiratory sensitisation classifications identify substances that can cause occupational asthma or contact dermatitis. CMR (carcinogenic, mutagenic, or reprotoxic) classifications trigger specific COSHH obligations, including the obligation to reduce exposure to as low as is reasonably practicable below any applicable WEL, and the requirement for health surveillance under regulation 11.

The exposure assessment section is the core analytical element of the form. It must identify all routes by which persons may be exposed — inhalation, skin contact, ingestion, and eye contact — and assess the likelihood and magnitude of exposure via each route. The frequency and duration of exposure are critical variables: a substance used for two hours every day poses a very different cumulative exposure risk from the same substance used occasionally for five minutes. Where an applicable WEL is listed in EH40, the assessment must consider whether existing controls are sufficient to ensure the WEL is not exceeded, and air monitoring may be required under regulation 10 to confirm this.

The control measures section must demonstrate that the employer has applied the COSHH hierarchy in selecting controls: first considering elimination, then substitution with a less hazardous alternative, then engineering controls including local exhaust ventilation (LEV), then administrative controls and safe systems of work, and finally PPE. The section must specify the type, standard, inspection frequency, and maintenance requirements for all engineering controls and PPE.

The health surveillance section addresses the regulation 11 obligation. For substances that can cause occupational asthma, dermatitis, or other specified conditions, a programme of health surveillance including pre-employment and periodic reviews must be implemented, with records kept for at least 40 years.

The emergency procedures section must cover all foreseeable scenarios — spillage, fire, accidental inhalation, skin or eye contact — and must be communicated to all persons who may be affected, including visiting contractors and emergency services. Emergency equipment including eyewash stations, spill kits, and first aid materials must be specified and maintained.