STSC Respirable Construction Hazards: Silica, Lead, and Asbestos

Question 1

What is OSHA's Permissible Exposure Limit (PEL) for respirable crystalline silica in construction under 29 CFR 1926.1153?

Accepted Answer

50 micrograms per cubic meter (μg/m³) as an 8-hour TWA

Answer

OSHA's 2016 silica rule set the PEL for construction at 50 μg/m³ as an 8-hour TWA — half the previous industry standard. The Action Level, which triggers enhanced monitoring and medical surveillance, is 25 μg/m³. Silicosis is an irreversible, potentially fatal lung disease.

Question 2

A crew is cutting fiber cement siding. Under OSHA's Table 1 of the silica standard (1926.1153), which control is REQUIRED to limit silica exposure during this task?

Accepted Answer

Wet cutting methods or use of a saw with an integrated HEPA-filtered vacuum

Answer

OSHA's Table 1 specifies task-specific engineering controls; for cutting fiber cement, wet methods or a vacuum with a HEPA filter are required. An employer who fully complies with Table 1 is deemed to have met the exposure assessment requirements — no separate air monitoring is needed.

Question 3

During an interior renovation, workers discover pipe wrap insulation that may contain asbestos. What is the supervisor's FIRST required action?

Accepted Answer

Stop work in the affected area and arrange for a licensed asbestos inspector to assess the material

Answer

OSHA 1926.1101 requires that suspect asbestos-containing material be treated as ACM until tested. Work must stop in the affected area, the area must be restricted, and a licensed inspector must assess and sample the material before any disturbance occurs.

Question 4

Lead exposure on construction sites most commonly occurs during which activity?

Accepted Answer

Torch cutting, grinding, or abrasive blasting of lead-based painted surfaces

Answer

Torch cutting, grinding, and abrasive blasting on surfaces coated with lead-based paint generate fine lead particles and fumes that are easily inhaled or ingested. Lead-based paint is common in structures built before 1978, making renovation and demolition work high-risk activities.

Question 5

Under OSHA's lead standard for construction (1926.62), a worker who is regularly exposed to lead at or above the Action Level must receive medical surveillance that includes:

Accepted Answer

Blood lead level (BLL) monitoring at regular intervals

Answer

Blood lead level (BLL) monitoring is the primary biomarker for lead absorption. OSHA's construction lead standard requires BLL testing for workers exposed at or above the Action Level of 30 μg/m³, with the frequency of testing increasing as BLL results rise.

(STSC) Safety Trained Supervisor Construction Practice Test

(STSC) Safety Trained Supervisor Construction Practice Test

STSC Respirable Construction Hazards: Silica, Lead, and Asbestos