Safety and Occupational Health
Safety and occupational health
This domain tests OSHA-based worker protection, especially for hazardous waste and emergency response. You must distinguish routine industrial hygiene from HAZWOPER emergency operations.
Core rules
- General Duty Clause: employers must provide a workplace free of recognized serious hazards when no specific standard applies.
- HAZWOPER (29 CFR 1910.120): 40-hour initial training plus 8-hour annual refresher for hazardous waste site workers; 24-hour training for occasional site visitors; emergency responders need appropriate levels.
- HazCom (1910.1200): labels, safety data sheets, and training.
- PPE and respiratory protection (1910.134): fit testing, medical evaluation, and cartridge change schedules.
- Confined space (1910.146): permit-required spaces need atmospheric testing, attendants, and rescue plans.
- LOTO (1910.147): isolate energy before servicing.
- Exposure limits: compare 8-hour time-weighted averages to PELs.
Worked example
A worker is exposed to 100 ppm of a solvent for 4 hours and 20 ppm for 4 hours. The 8-hour TWA = (100×4 + 20×4) / 8 = 60 ppm. If the PEL is 50 ppm, the exposure exceeds the limit even though neither individual sample exceeded 100 ppm. Controls: engineering first, then administrative, then PPE.
Traps
Using the highest short-term sample instead of the TWA; assuming PPE eliminates the need for monitoring; missing annual refresher training; and entering a permit space without testing oxygen, flammables, and toxics.