Potentially Hazardous Noise is defined as which of the following?

• A. Exposure to steady-state noise having a 8-hour TWA noise level greater/equal to 85 dBA.
• B. Exposure to any noise above 75 dBA.
• C. Impulse noise only
• D. Noise exposure below 65 dBA

Answer: (A)

Potentially hazardous noise is defined by how loud and how long the noise lasts over a typical work shift. If the noise is steady over an 8-hour period and the time-weighted average reaches 85 dBA or higher, that exposure is considered potentially hazardous to hearing, so protective measures are needed. The 8-hour TWA is a way of averaging fluctuating noise levels across a full shift, not just a momentary spike. Exposures with lower averages (for example, below 85 dBA over 8 hours) are not classified as potentially hazardous in this standard sense. Impulse or peak noises are treated separately from this steady-state definition, and very low noise levels (well below 65 dBA) are not hazardous over a work shift.