Occupational Health and Safety
What this domain tests
This domain checks whether you identify hazards before work starts, apply the hierarchy of controls, and name the specific regulation, PPE standard, or procedure that governs a task. Items are scenario-based: a galvanized weld in a basement, a curb on a roof, a ladder to a mezzanine.
Legal framework and the internal responsibility system
- OHS is provincial or territorial. The Act sets duties for the employer, the supervisor, and the worker; everyone owns safety on site.
- Three worker rights: to know the hazards, to participate in safety, and to refuse work you have reasonable cause to believe is unsafe.
- WHMIS 2015 (GHS-aligned): supplier labels, pictograms, and a 16-section SDS must be available for every controlled product on site.
- A competent supervisor has the knowledge, training, and experience to organize the work and identify hazards.
Hazard control and PPE
Apply the hierarchy: eliminate, substitute, engineer (guards, local exhaust, ventilation), administrate (procedures, rotation), then PPE. Standards the trade relies on: CSA Z94.3 eye and face protection, CSA Z195 protective footwear, CSA Z94.2 hearing protection, and a respirator fitted under the employer's program.
Work at height, energy, and hot work
- Fall protection is generally required at 3 m (10 ft) or wherever a fall hazard exists. Guardrails first, then travel restraint, then fall arrest.
- Ladders: 4:1 slope, extending 1 m above the landing, three-point contact, secured top and bottom.
- Lockout/tagout for brakes, rolls, and air-handling equipment. Hot work needs a permit, a fire watch, and monitoring after the work ends.
Welding and coating hazards
Zinc coating on galvanized steel produces zinc-oxide fume. Grind the coating back at least 50 mm (2 in.) from the weld, use local exhaust, and expect metal fume fever to appear hours later. Assume asbestos, lead, or silica in buildings from before the 1990s until sampling proves otherwise.
Worked example: fall clearance
A fixed anchor sits 3.0 m above the floor. An energy-absorbing lanyard needs 1.5 m free fall + 1.0 m deceleration + 1.8 m worker height (D-ring to feet) + 0.6 m safety factor = 4.9 m total clearance. With only 3.0 m available, the worker hits the floor. Fix it by raising the anchor, shortening the lanyard, or using a self-retracting lifeline mounted overhead.
Traps that cost marks
- Treating fall restraint and fall arrest as interchangeable.
- Returning a harness to service after it has arrested a fall; it must be removed from service.
- Quoting a manufacturer's rule when the question asks for the regulatory minimum.