Final answer:
According to OSHA standards, when an employee's noise exposure exceeds an 8-hour TWA sound level of 85 dB, hearing protection must be worn.
Step-by-step explanation:
The Occupational Safety and Health Administration (OSHA) has set standards for noise exposure in the workplace. When an employee's noise exposure exceeds an 8-hour Time-Weighted Average (TWA) sound level of 85 decibels (dB), hearing protection must be worn.
This means that if an employee is exposed to noise levels that average 85 dB or higher over an 8-hour period, they are required to wear hearing protection to prevent hearing damage. This is based on the recommendation of several government agencies and health-related professional associations.