Control of Substances Hazardous to Health (COSHH)

COSHH stands for Control of Substances Hazardous to Health and refers to the UK regulations that require employers to control substances that could harm workers’ health. The legislation applies to almost any workplace where chemicals, fumes, dusts, mists, vapours, gases or biological agents are present. In practice, this means that employers must identify potentially harmful substances, assess exposure risks, and implement measures to eliminate or reduce those risks as far as reasonably possible. COSHH covers substances used directly in work processes, produced during work activities, or incidental substances such as cleaning agents or naturally occurring dusts.

The core responsibilities under COSHH include risk assessment, exposure prevention, training, and monitoring of hazardous materials. A key principle is that prevention should always come before protective equipment; in other words, employers should first explore safer alternatives or safer processes before relying on PPE. If hazards cannot be removed entirely, controls such as ventilation, containment, safe handling procedures and regular supervision should be used. In certain cases, employers must also measure exposure levels and carry out health surveillance when substances carry long-term or serious risks. Employees have duties too, including following safety instructions, using provided controls correctly, and reporting issues that could increase risk.

COSHH matters because harmful substances can cause a wide range of health problems, from short-term irritation of skin, eyes and lungs, to long-term or chronic conditions including asthma, lung disease, and even certain types of cancer. Many risks are not immediately visible, and symptoms may develop after long-term exposure, which makes proactive risk management essential. The regulations therefore encourage a systematic approach: identify hazards, assess risks, implement controls, monitor exposure, record findings, and review procedures regularly so that controls remain effective.

COSHH does not only apply to traditionally hazardous industries such as manufacturing or construction. It is also relevant in laboratories, healthcare settings, cleaning services, office environments and retail workplaces, where apparently ordinary products may still contain hazardous components. Even small businesses using only a few cleaning chemicals must comply. By following COSHH, organisations reduce health risks, lower costs linked to sickness absence, ensure compliance with UK law and support a safer workplace culture.