COS/Advanced/TBT-COS-042

Bentonite Handling and Disposal

COSHH & Hazardous Substances › Advanced › Bentonite Handling and Disposal

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Bentonite is a clay-based slurry used in piling, diaphragm walling, and tunnelling to support excavations.
It creates a hydrostatic pressure against the excavation walls, preventing collapse during construction.
Bentonite slurry is extremely slippery — it creates serious slip hazards on walkways and working platforms.
Dry bentonite powder is a respiratory irritant and must be handled with dust controls in place.
COSHH 2002 requires a risk assessment for both the powder handling and slurry contact hazards.
Used bentonite slurry is classified as waste and must be disposed of through a licensed waste facility.
Bentonite must not be discharged into watercourses — it smothers aquatic life and blocks drainage systems.
The slurry is mixed on site using high-shear mixers and pumped through pipework to the working area.
Skin contact with bentonite slurry causes drying and irritation — wash off promptly after exposure.
Bentonite storage silos require confined space entry procedures for inspection and maintenance access.

Slip hazard	Bentonite slurry on walkways, platforms, and access routes creates an extremely dangerous slip risk for all workers.
Environmental pollution	Bentonite discharged into watercourses kills fish and aquatic organisms by smothering and reducing oxygen levels.
Respiratory irritant	Dry bentonite powder causes coughing, eye irritation, and airway inflammation if inhaled without RPE.

Don't

Wear waterproof overalls, gloves, and boots when working with bentonite slurry.
Use dust suppression or RPE when handling dry bentonite powder at the silo.
Clean up bentonite spillages on walkways and platforms immediately to prevent slips.
Contain all bentonite slurry using bunds, tanks, and settlement systems on site.
Dispose of used bentonite through a licensed waste carrier with transfer documentation.
Wash bentonite off skin promptly using clean water and mild soap after contact.
Maintain slurry pipework connections securely to prevent leaks and burst joints.
Install anti-slip matting on platforms and access routes near bentonite operations.
Follow confined space procedures for any entry into bentonite storage silos.
Brief all workers on the slip and environmental risks before bentonite work begins.

DON'T discharge bentonite slurry into drains, ditches, or watercourses.
DON'T walk through bentonite-contaminated areas without appropriate slip-resistant footwear.
DON'T handle dry bentonite powder without dust suppression or respiratory protection.
DON'T leave bentonite spills on walkways, steps, or vehicle access routes uncleaned.
DON'T mix bentonite in open containers where wind can carry dust to other workers.
DON'T enter a bentonite silo without a confined space permit and rescue plan.
DON'T pump waste bentonite off site without a licensed carrier and waste documentation.
DON'T allow bentonite slurry to overflow from settlement tanks onto open ground.
DON'T ignore skin dryness or irritation after bentonite contact — wash and moisturise.
DON'T store dry bentonite bags where they can get wet and create a slip hazard.

See also: COSHH Awareness | Silt and Sediment Control

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