COS/Controls/TBT-COS-018

Man-Made Mineral Fibres (MMMF)

COSHH & Hazardous SubstancesControlsMan-Made Mineral Fibres (MMMF)

Man-Made Mineral Fibres (MMMF)

Toolbox Talk Record

Ref: TBT-COS-018  |  Issue: 1  |  Date: March 2026
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What?

  • Man-made mineral fibres include glass wool, rock wool, slag wool, and ceramic fibres used as insulation.
  • MMMF products are widely used for thermal insulation, fire protection, and acoustic treatment in buildings.
  • Handling MMMF causes immediate skin irritation, itching, and redness from fibre contact with exposed skin.
  • Inhaling MMMF dust irritates the nose, throat, and upper airways, causing coughing and discomfort.
  • Refractory ceramic fibres (RCF) are classified as possible human carcinogens and have stricter exposure limits.
  • The workplace exposure limit for MMMF other than RCF is 5 mg/m³ for total inhalable dust.
  • Cutting, tearing, and compressing MMMF releases higher concentrations of airborne fibres.
  • COSHH 2002 requires assessment and control of MMMF exposure during installation and removal.
  • Long sleeves, gloves, and eye protection significantly reduce skin and eye irritation from MMMF.
  • Washing MMMF-contaminated clothing separately prevents fibre transfer to other garments.

Why?

Skin irritationMMMF fibres embed in skin causing intense itching, redness, and dermatitis that affects worker comfort and health.
Respiratory effectsInhaling MMMF dust irritates the airways and, for ceramic fibres, carries a potential cancer risk.
Legal dutyCOSHH 2002 requires employers to assess MMMF exposure and provide appropriate controls and PPE.
Do Don't
  • Wear long sleeves, gloves, and eye protection when handling MMMF insulation
  • Use sharp knives rather than tearing to cut MMMF — clean cuts release fewer fibres
  • Work in well-ventilated areas to disperse airborne fibres during installation
  • Wear RPE when cutting or disturbing large quantities of MMMF in enclosed spaces
  • Complete a COSHH assessment for MMMF products before starting insulation work
  • Wash hands, face, and forearms before eating, drinking, or leaving the work area
  • Shower after prolonged MMMF handling to remove embedded fibres from the skin
  • Launder MMMF-contaminated work clothing separately from personal clothes
  • Identify refractory ceramic fibres (RCF) and apply stricter controls where present
  • Dispose of MMMF waste in sealed bags to prevent fibre release during transport
  • DON'T handle MMMF insulation with bare arms, hands, or without eye protection
  • DON'T tear MMMF products by hand — use a sharp blade for cleaner, lower-dust cuts
  • DON'T blow MMMF dust from clothing with compressed air — it spreads fibres everywhere
  • DON'T rub or scratch irritated skin — it pushes fibres deeper and worsens irritation
  • DON'T install MMMF in enclosed spaces without ventilation and RPE
  • DON'T eat or drink before washing MMMF fibres from your hands and face
  • DON'T dispose of MMMF offcuts loose on site — bag them to contain fibres
  • DON'T wash MMMF-contaminated clothing with your personal laundry
  • DON'T confuse standard MMMF with refractory ceramic fibres — RCF needs stricter controls
  • DON'T ignore persistent skin or respiratory symptoms — report them to occupational health

See also: COSHH Awareness | Roof Insulation Installation

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