Introduction
Many workplaces involve contact with hazardous substances such as chemicals, dust, fumes or solvents. Without proper safety controls, this exposure can cause serious illnesses affecting the lungs, skin, or other parts of the body. If your condition is linked to unsafe working conditions, you may be entitled to claim compensation.
This page explains what hazardous substance claims involve, when employers are responsible, what evidence helps, and how much you could claim.
At a glance
- Over 1,200 cases of workplace injuries linked to exposure to harmful substances were reported under RIDDOR in 2022/23, including chemical inhalation and skin disease (Source: WAAC analysis of the HSE RIDDOR data published 2024)
- Hazardous substances include chemicals, dust, fumes, gases and solvents.
- Employers must follow the Control of Substances Hazardous to Health (COSHH) Regulations.
- Conditions linked to exposure include occupational asthma, dermatitis, silicosis and lung disease.
- You usually have three years from diagnosis or “date of knowledge” to start a claim.
Typical hazardous substance work ilnesses?
Exposure to harmful substances can happen through inhalation, skin contact or accidental ingestion. Over time, repeated exposure can cause long-term health problems. Common examples include:
- Occupational asthma – breathing difficulties caused by dust, fumes or vapours.
- Dermatitis – skin inflammation from contact with chemicals or cleaning agents.
- Silicosis – lung disease caused by inhaling silica dust from stone, concrete or sand.
- Chronic obstructive pulmonary disease (COPD) – caused or worsened by workplace dust or fumes.
Examples of hazardous substances and illnesses
| Substance | Typical workplace | Possible illness or condition |
|---|---|---|
| Silica dust | Construction, stone cutting, quarrying | Silicosis, lung cancer, COPD |
| Solvents | Printing, painting, cleaning | Dermatitis, headaches, neurological symptoms |
| Isocyanates | Spray painting, plastics, foams | Occupational asthma, respiratory irritation |
| Cleaning agents | Hospitality, healthcare, janitorial work | Dermatitis, eye and lung irritation |
| Metal fumes | Welding, smelting, foundries | Metal fume fever, long-term lung conditions |
Am I eligible to claim?
You can usually claim if:
- You were diagnosed with a work-related illness in the last three years, or only recently realised it was linked to your job (the “date of knowledge”), and
- Your employer failed to take reasonable steps to reduce or prevent exposure, such as providing PPE, ventilation, or training, and
- Medical evidence links your illness to workplace exposure.
If you are unsure, see Do I have a claim and The claim process.
How much compensation can I claim?
Compensation has two parts:
- General damages: for pain, suffering and loss of amenity. Awards vary depending on severity – for example, permanent breathing problems attract higher awards than mild dermatitis.
- Special damages: financial losses such as treatment costs, prescriptions, travel expenses, lost income, future loss of earnings, specialist equipment and care needs.
Keep medical reports, receipts and payslips to support your claim.
When is my employer responsible?
Employers have duties under the Health and Safety at Work Act and the COSHH Regulations to protect workers from hazardous substances. They must:
- Identify and assess risks from hazardous substances.
- Replace dangerous chemicals with safer alternatives where possible.
- Provide PPE such as respirators, gloves or protective clothing.
- Ensure safe ventilation, extraction and storage of substances.
- Train staff on safe handling and emergency procedures.
If your employer ignored these duties, they may be liable for your illness. For more, see HSE: COSHH guidance.
Evidence that strengthens a claim
- Medical records and diagnostic reports confirming your condition.
- Occupational history showing exposure at work.
- Health and safety risk assessments or inspection records.
- Witness statements from colleagues.
- Records showing PPE was not provided or enforced.
See How to gather evidence after a work accident and The role of medical experts.
Time limits for hazardous substance claims
The standard time limit is three years from diagnosis or from when you first realised your illness was linked to work (the “date of knowledge”). Exceptions apply if you were under 18 or lack capacity. Read more in time limits for injury claims.
FAQs
What if I worked for several employers in hazardous environments?
You may still claim. Liability can be shared between employers if multiple exposures contributed to your condition.
What if my employer no longer exists?
You may still claim against their insurer. See claiming if your employer has ceased trading.
Do I need a medical assessment?
Yes. An independent medical expert will confirm diagnosis, cause and long-term outlook. See What happens at a medical appointment.
Next steps
If you have been diagnosed with an illness linked to workplace exposure, you may be entitled to both benefits and compensation. See benefits after a workplace accident and contact a solicitor to discuss your claim.
Our work injury advisors will:
- Offer free, impartial advice
- Explain how No Win, No Fee works
- Recommend the right solicitor
External references
- HSE: Control of Substances Hazardous to Health (COSHH) - provides guidance on managing risks from hazardous substances in the workplace to prevent illnesses and injuries.
- NHS: Occupational asthma - offers information on occupational asthma caused by exposure to hazardous substances, including symptoms and treatment.
- Personal Protective Equipment at Work Regulations 2002 - outlines employer obligations to provide PPE to protect against hazardous substance exposure.
- GOV.UK: Compensation after an accident or injury - explains the process for claiming compensation for illnesses caused by exposure to hazardous substances at work.
About the author
Chris Salmon is a legal commentator and co-founder of Quittance Legal Services. He has written extensively about workplace accidents, employment rights and the claims process. Chris's work has been cited in national media and he regularly contributes practical guidance to help injured workers understand their options.
Last reviewed September 2025 by Chris Salmon