Laboratory Safety and Hazardous Substance Control
What is examined
Hazard identification and control in a working dental laboratory - dusts, vapours, acids, heat, electricity, compressed gas and waste streams.
Hazardous substances
- Under the Hazardous Substances Regulations 2017, keep an inventory, hold current safety data sheets, label every decanted container, and store incompatible chemicals apart.
- Methyl methacrylate monomer is flammable, volatile, a skin sensitiser and a respiratory irritant. Use local exhaust ventilation, keep lids on, avoid skin contact, and never decant near a flame or Bunsen burner.
- Hydrofluoric acid causes deep burns and systemic hypocalcaemia. Use a dedicated area and PPE, keep calcium gluconate gel within reach, and never store it in glass.
Dust and fume
- Silica and cristobalite dust cause silicosis; PMMA and plaster dust irritate the airway; some base-metal alloys contain beryllium, cobalt and chromium, and nickel sensitisation is common.
- Control: wet trimming where possible, local exhaust extraction at the bench, fit-tested respirators rather than a surgical mask, eye protection, and no eating or drinking in the laboratory.
Physical and waste hazards
- Gas cylinders secured upright; torch work kept away from monomer and paper.
- Electrical safety: RCD protection, tested equipment, undamaged cords.
- Amalgam waste through a separator, sharps into rigid containers, plaster never down the sink (it sets and blocks drains), and waste segregated for a licensed contractor.
Worked example
A technician develops a rash on the fingertips after months of handling uncured acrylic. This is allergic contact dermatitis to monomer. The control is not barrier cream - it is appropriate gloves, closed mixing, local exhaust ventilation and a health assessment.
Traps
- Treating a dust mask as respiratory protection.
- Storing hydrofluoric acid in glass among other acids.
- Washing plaster slurry down the sink and creating a set plug in the drain.