Occupational Safety, Health and Environment
What the exam tests
Hazard and risk vocabulary, the hierarchy of controls, PPE, safety signs, fire safety and extinguisher use, first aid, ergonomics, occupational disease, housekeeping and emergency response.
Core rules
- Hazard is the potential to harm; risk is the likelihood and severity of that harm actually occurring.
- Control hierarchy, most effective first: elimination, substitution, engineering controls such as guards and ventilation, administrative controls such as training, rotation and permits, then PPE. PPE is last because it protects one person and fails if worn or fitted wrongly.
- Sign shapes: red circle with a slash means prohibition; yellow triangle means warning; blue circle means mandatory, for example wear goggles; green square means safe condition or escape route.
- Fire triangle: fuel, oxygen, heat, remove one and the fire stops. Extinguisher classes: A solids (water), B flammable liquids (foam or CO2), C gases, D metals, K cooking oils. Electrical fires need CO2 or dry powder, never water. PASS: pull, aim, squeeze, sweep.
- Ergonomics: screen at eye level, feet supported, wrists neutral, micro-breaks, and lift with the legs instead of twisting.
- Occupational diseases: silicosis from silica dust, asbestosis, lead poisoning, contact dermatitis, noise-induced hearing loss, musculoskeletal disorders.
- Emergency: know exits and the assembly point, keep them clear, follow the warden, and report every near miss.
Worked example
A grinding section measures 96 dB, against a limit of 90 dB for an eight-hour day. Reasoning: first ask whether grinding can be eliminated or the process substituted; then enclose the machine and fit silencers (engineering); then rotate jobs and post signage (administrative); hearing protection is issued last and its use audited. Answering 'issue ear plugs' scores low because it starts at the bottom of the hierarchy. Also, with a 3 dB exchange rate the safe duration halves every 3 dB, so 96 dB is safe for only about 2 hours, not 8.
Marks-losing traps
- Choosing PPE as the first control.
- Using water on an electrical or cooking-oil fire.
- Confusing a warning triangle with a mandatory blue circle.
- Dismissing a near miss as 'no accident, nothing to report'.