Occupational Health & Safety (OHS): Definition, Hazards, Tools & Professional Role

Occupational Health and Safety (OHS)—also termed OSH, WHS, or occupational hygiene—is the multidisciplinary field dedicated to anticipating, recognizing, evaluating, controlling, and preventing hazards that threaten the safety, health, and well-being of workers and others affected by the workplace environment.

Scope of Hazards Addressed

Category	Examples
Physical	Noise, vibration, radiation (ionizing/non-ionizing), temperature extremes, pressure, illumination, ergonomics (repetition, force, posture)
Chemical	Toxics (solvents, heavy metals, pesticides), corrosives, irritants, sensitizers, asphyxiants, carcinogens, nanoparticles
Biological	Bacteria, viruses, fungi, parasites, prions, bloodborne pathogens, zoonoses, endotoxins
Psychosocial	Work stress, burnout, harassment/bullying, violence, shift work, job insecurity, effort-reward imbalance
Mechanical / Safety	Machine guarding, lockout/tagout, fall protection, confined space, electrical, fire/explosion, struck-by/caught-in
Ergonomic	MSD risk factors: repetition, force, awkward posture, static load, vibration, contact stress

Core OHS Methodology (The “OHS Cycle”)

1. Hazard Identification: Inspections, JSA/JHA, SDS review, incident reports, worker reports, medical surveillance, Hygiene monitoring.
2. Risk Assessment: Likelihood × Severity → Risk Matrix. Qualitative, semi-quantitative, or quantitative (QRA, LOPA).
3. Control Selection (Hierarchy): Elimination → Substitution → Engineering → Administrative → PPE. ALARP (As Low As Reasonably Practicable).
4. Implementation: SOPs, training, maintenance, procurement specs, signage, permits (LOTO, confined space, hot work).
5. Verification & Monitoring: Inspections, audits, exposure sampling, health surveillance, leading/lagging indicators, incident investigation (RCFA).
6. Continuous Improvement: PDCA, management review, technology adoption, regulatory updates.

OHS Professional Activities

• Develop/manage SMS (Safety Management System) – ISO 45001, ANSI Z10, OHSAS 18001 (legacy).
• Conduct exposure assessments (air, noise, ergonomics, biological).
• Investigate incidents (TapRooT, 5 Whys, ICAM) – focus on system failures, not blame.
• Design/deliver training (competency-based, adult learning principles).
• Advise on engineering controls, PPE selection, emergency planning.
• Medical surveillance programs (respirator clearance, audiometry, biologics monitoring).
• Liaise with regulators (OSHA, WorkSafe, HSE), workers’ comp, unions, contractors.
• Lead culture transformation (BBS, HOP, Safety-II, Learning Teams).

Business Value

• Injury/illness reduction → lower workers’ comp, lost time, turnover.
• Productivity, quality, morale gains.
• Legal compliance, ESG performance, investor/stakeholder confidence.
• Reputation, social license to operate.

OHS is not a cost—it’s an investment in human capital and organizational resilience.