What is the OSHA action level for asbestos exposure in construction?

• A. 0.1 f/cc averaged over an 8-hour workday.
• B. 0.01 f/cc averaged over an 8-hour workday.
• C. 0.001 f/cc averaged over an 8-hour workday.
• D. 0.05 f/cc averaged over an 8-hour workday.

Answer: (B)

In OSHA’s construction asbestos standard, there are two important exposure thresholds: an action level and a permissible exposure limit. The action level is 0.01 fibers per cubic centimeter (f/cc) averaged over a full 8-hour workday. This lower threshold is meant to trigger proactive steps—such as monitoring, exposure assessments, and protective measures—before the exposure gets close to the limit that’s allowed. If workers are expected to be exposed at or above this level, the employer must assess the actual exposure and start implementing controls to keep exposures down.

The higher threshold, the permissible exposure limit, is 0.1 f/cc over 8 hours. This is the maximum legally allowed average exposure; once exposures approach or exceed this level, more stringent controls and protections come into play. The other numbers listed don’t align with OSHA’s established action level for construction asbestos, which is why the correct choice is the 0.01 f/cc value.