Free OHST Practice Questions

Correct answer: A - 3.2

TRIR = (Recordable Cases × 200,000) ÷ Hours Worked. For this case: (8 × 200,000) ÷ 500,000 = 3.2. The 200,000 base represents 100 full-time workers × 2,000 hours/year, allowing rate comparison between facilities of different sizes. A common mistake is using 100,000 (which gives 1.6) or forgetting to multiply by 200,000 (which gives 0.000016).

Correct answer: C - Eliminate the noise source

The hierarchy of controls - most to least preferred - is: (1) Elimination, (2) Substitution, (3) Engineering controls, (4) Administrative controls, (5) PPE. Elimination removes the hazard entirely and is most reliable because it doesn't depend on human behavior or equipment maintenance. PPE is last-resort because it only protects the wearer if used correctly every time. The hierarchy is referenced in ANSI/ASSP Z10 (OHSMS) and NIOSH guidance.

Correct answer: C - Stop the entry immediately

29 CFR 1910.146 (Permit-Required Confined Spaces) requires atmospheric testing (oxygen 19.5-23.5%, LEL <10%, toxics below PEL) and an entry permit BEFORE entry. Untested permit-required confined spaces have caused some of the most severe occupational fatalities - often killing both the entrant AND would-be rescuers. Stop-work authority is a fundamental safety responsibility that overrides production pressure and the chain of command. Documentation and discussion happen AFTER the immediate hazard is controlled.

Correct answer: B - 6 feet maximum

OSHA limits free fall to 6 feet maximum (29 CFR 1926.502(d)(16)(iii)). Combined with deceleration distance of 3.5 feet, the total fall distance can reach ~9.5 feet before arrest is complete. This is why anchorage point height and lanyard length matter so much: if a worker tied off at foot level falls from a 5-foot platform, free fall could exceed 6 feet. The system must also limit Maximum Arresting Force (MAF) to 1,800 lbf on the body - the threshold above which serious internal injury becomes likely.

Correct answer: B - 87% of rated capacity

As sling angle decreases from vertical (90°), tension in each leg increases dramatically. Common reduction factors: 90° = 100%, 60° = 87%, 45° = 71%, 30° = 50%. At 30°, EACH leg carries the full load weight - a frequent cause of rigging failure. Riggers should always measure from horizontal and reference manufacturer load charts. ASME B30.9 prohibits sling angles below 30° from horizontal because forces become unmanageable.

Correct answer: A - APF × PEL

MUC = Assigned Protection Factor (APF) × Permissible Exposure Limit (PEL). For example, a half-mask APR (APF = 10) used against benzene (PEL = 1 ppm) has an MUC of 10 ppm. Two critical limits apply: (1) MUC may NEVER exceed the IDLH concentration regardless of calculation, and (2) MUC may not exceed the manufacturer's maximum use limit. APFs come from OSHA Table 1 in 29 CFR 1910.134: half-face APR = 10, full-face APR = 50, full-face PAPR = 1,000, SCBA pressure-demand = 10,000.

Correct answer: D - 1,000

Per 29 CFR 1910.134 Table 1, APFs reflect the workplace level of respiratory protection a properly functioning respirator provides: half-face APR = 10, full-face APR = 50, loose-fitting PAPR = 25, tight-fitting full-face PAPR = 1,000 (with manufacturer evidence), supplied-air pressure-demand full-face = 1,000, and SCBA pressure-demand = 10,000. The PAPR's high APF comes from positive pressure inside the facepiece - even a small leak pushes air OUT rather than letting contaminants in. Without manufacturer evidence, the default tight-fitting full-face PAPR APF is 50.

Correct answer: A - 10 seconds and 55 feet

ANSI Z358.1 specifies that emergency eyewashes must be reachable within 10 seconds of travel time, generally interpreted as approximately 55 feet on an unobstructed path. Eyewashes must also deliver tepid water (60-100°F) at minimum 0.4 GPM for 15 continuous minutes - long enough to neutralize most chemical exposures before permanent eye damage. Plumbed units require WEEKLY activation testing and ANNUAL full inspection. The 10-second rule reflects that strong acids and bases can cause irreversible corneal damage in under 30 seconds.

Correct answer: B - 8 hours

OSHA requires fatality reporting within 8 HOURS of the employer learning of the death (29 CFR 1904.39). In-patient hospitalization, amputation, and loss of an eye must be reported within 24 hours. Reporting can be done by phone to the nearest OSHA Area Office, the OSHA 24-hour hotline (1-800-321-OSHA), or the online reporting application. Failure to report a fatality timely is a serious violation with significant penalties. These reporting timelines apply regardless of weekends, holidays, or after-hours occurrence - a Friday-night fatality must still be reported by Saturday morning.

Correct answer: B - Disclose the conflict to the employer

BCSP Code of Ethics Standard 2 (honesty, fairness, impartiality) and Standard 6 (highest integrity) require disclosure of any financial interest, relationship, or circumstance that could appear to influence professional judgment. The correct response is full transparent disclosure - letting the employer decide whether the OHST should recuse, proceed with oversight, or continue normally. Hiding the interest violates the Code; declining without explanation deprives the employer of needed information. Effective July 2023, BCSP recertification requires 5 hours of ethics training every 5-year cycle, reflecting how central ethical decision-making is to the credential.