Occupational Health and Safety, and Environmental Practices
What this domain tests
The exam checks whether you can recognize hazards before they injure someone, apply the right control in the right order, and keep the shop's waste, fumes, and fluids out of the environment. Questions mix legislation, chemistry, and practical shop decisions.
The legal and administrative frame
- Provincial and territorial OHS acts set the internal responsibility system: employer, supervisor, and worker duties; the right to know, participate, and refuse unsafe work.
- WHMIS 2015 requires supplier labels and a 16-section SDS before a controlled product is used.
- CSA W117.2 covers welding, cutting, and allied process safety; CSA Z94.3 covers eye and face protection; CSA Z462 covers arc flash.
- Joint health and safety committees, incident reporting, and formal hazard assessments are expected, not optional.
Control the hazard, not just the worker
Apply the hierarchy: eliminate, substitute, engineer, administer, then PPE. Practical controls in a fabricating shop:
- Lockout/tagout: isolate every energy source, bleed hydraulic and pneumatic accumulators, block gravity loads, then verify zero energy.
- Hot work permit, fire watch, combustible clearance, and fire blankets; welding screens protect others from arc flash.
- Local exhaust ventilation at the arc; stainless fume carries hexavalent chromium, so extraction plus respiratory protection.
- Confined space entry: permit, atmospheric test for oxygen, flammables and toxics, ventilation, attendant, rescue plan.
- Compressed gas: cylinders upright and secured, caps on, fuel gas and oxygen separated or barriered, acetylene never above 103 kPa gauge and never through copper.
Environmental practice
Segregate scrap by alloy because mixing stainless with carbon downgrades the load and causes rust contamination. Spent cutting fluid, hydraulic oil, and solvent are hazardous waste: secondary containment, labelled containers, no drains. Chlorinated degreasers on stainless risk stress-corrosion cracking, so use approved alternatives. Aluminum grinding dust is combustible, so use wet collection and disciplined housekeeping.
Worked example
A fabricator must weld inside a 1.2 m deep steel pit. Depth alone does not decide. Ask whether entry is restricted, whether the atmosphere could become hazardous, and whether engulfment is possible. If yes to any, treat it as a confined space: test, ventilate, permit, attendant, harness and retrieval line, and a gas monitor worn continuously. If the pit is open, ventilated, and tested safe, document the assessment.
Traps
- Reaching for PPE first and ignoring engineering controls.
- Locking the disconnect but leaving stored energy in accumulators, springs, or raised loads.
- Assuming an open-top pit is not a confined space.
- Mixing alloy scrap or pouring coolant down the drain.