Quick answer: Workshop degreasing is a COSHH-regulated activity: degreasing products — whether solvent-based, alkaline or detergent-based — are substances hazardous to health requiring formal risk assessment and exposure controls. Hot-water pressure washing with a water-miscible alkaline detergent outperforms solvent degreasers for most hydrocarbon contamination, produces a single manageable liquid waste stream, and requires less chemical for the same cleaning outcome. Wash-water from workshop degreasing is trade effluent requiring consent before discharge to sewer.
Workshop degreasing sits in a compliance grey area for many operators. The task is necessary — accumulated grease, oil and fuel residue on workshop floors, machinery, vehicle bays and plant is a slip hazard, a fire risk and a contamination problem. But the method used to degrease, the products involved, and what happens to the run-off afterwards all carry regulatory implications that most workshops have never formally assessed.
For maintenance workshops, plant depots, manufacturing facilities and vehicle service bays, workshop degreasing is a COSHH activity with implications for operative safety, product handling, drainage consent and environmental compliance.
Common failure modes: solvent-based degreasers used without adequate ventilation or LEV; no COSHH assessment for products in use; wash-down run-off going to drain without consent or treatment; cold water compensated with high chemical volumes increasing contamination load; assuming no consent is needed because the floor drain goes to foul sewer — trade effluent consent applies to foul sewer discharge where waste contains trade process residues above threshold concentrations.
COSHH Regulations 2002 — degreasing products are substances hazardous to health. Employers must assess risk, implement controls in the correct hierarchy, and demonstrate operative exposure is controlled below the relevant WEL. Trade Effluent Consent (Water Industry Act 1991) — wash-water containing degreaser residue and hydrocarbon contamination requires consent from the water company before discharge to public sewer. Environmental Permitting Regulations 2016 — run-off reaching surface water is a pollution risk. PSSR 2000 — steam or hot water pressure equipment requires maintenance and inspection under the Pressure Systems Safety Regulations.
Hot water at 70–90°C emulsifies grease and oil mechanically, achieving the same result as solvent degreasers with lower product consumption and without the vapour risk in enclosed spaces. Hot water degreasing produces a single liquid waste stream — contaminated wash-water — rather than the hazardous waste wipes and rags that solvent degreasing generates. Switching from cold to hot water typically reduces both water consumption and chemical dosing for the same cleaning outcome, directly reducing run-off volume and contamination load.
Related pages
