Mineral Wool / Glass Fibre / Stone Wool (MMMF)
COSHH assessment
A COSHH assessment for mineral wool / glass fibre / stone wool (mmmf) on a UK construction site: what it does to people, how it gets into them, the controls that stop it, the PPE for what is left, and what to do when it goes wrong. Copy it into your assessment and change what does not fit your job.
Hazards to health
Mechanical irritant, skin, eye and upper respiratory irritation. Modern bio-soluble MMMF (post-2002) is not classified as a carcinogen (IARC Group 3). Older fibres (pre-2002 Special Purpose Fibres, refractory ceramic fibres), IARC Group 2B, requiring stricter controls.
Routes of exposure
Skin contact, Inhalation, Eye contact
Control measures
- Cut with sharp knife or saw, do not tear or break (releases more fibre).
- Vacuum off-cuts with M-class vac, do not blow down.
- Loose-fitting long sleeves and trousers, fibres trap in tight cuffs.
- Adequate ventilation.
- Wash work clothes separately from domestic.
- Identify pre-2002 product or RCF and treat as higher-hazard with P3 RPE and disposable coveralls.
- No rubbing of eyes or skin during work.
PPE for what is left
- FFP3 disposable mask (FFP2 acceptable for short tasks with modern bio-soluble fibre), Safety goggles, Loose-fitting nitrile or leather gloves, Disposable coveralls or washable long sleeves, Hood for overhead work
Emergency procedures
- Skin: rinse gently with cool running water, hot water opens pores and worsens irritation.
- Adhesive tape can lift surface fibres.
- Eyes: do not rub.
- Irrigate gently with eyewash for 15 minutes, A&E if irritation persists.
- Inhalation: fresh air, GP if cough lasts >24 hrs.
Questions people ask
Do I need a COSHH assessment for mineral wool / glass fibre / stone wool (mmmf)?
If the substance is hazardous to health and your work exposes people to it, yes. The Control of Substances Hazardous to Health Regulations 2002, regulation 6, require a suitable and sufficient assessment before the work starts, with the significant findings recorded if you employ five or more. The safety data sheet is an input to the assessment, not a substitute for it. Guidance, not legal advice.
What is the difference between a safety data sheet and a COSHH assessment?
The data sheet is the manufacturer describing the product in general. The assessment is you describing how your people use it on your job: how much, how often, for how long, in what ventilation, with what controls. Two firms using the same tin can have very different assessments.
What is a WEL?
A Workplace Exposure Limit, the maximum airborne concentration averaged over a reference period, set in HSE document EH40. Where one applies to this substance it is stated in the hazards above; where it does not, the duty to reduce exposure so far as is reasonably practicable still stands.
Is PPE enough?
No. COSHH puts PPE last: eliminate the substance, substitute for something less harmful, control at source with ventilation and enclosure, then organise the work to reduce exposure, and only then PPE for what is left. An assessment that jumps straight to gloves and a mask is the kind an inspector questions. Guidance, not legal advice.
How often should it be reviewed?
When the product, the method, the quantities or the people change, if there is any sign the controls are not working, and at least every year or so regardless. Health surveillance may be required where exposure could cause an identifiable disease, such as dermatitis or occupational asthma.
The COSHH assessment writes itself
Pick the substance in the SiteLynx RAMS editor and the COSHH assessment fills in with the hazards, controls and PPE, alongside the HAVS and noise assessments for the tools you chose. Signed on site on a phone. 14 days free.
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