Noise protection is needed by many workers in concrete plants. Some vibrators and other equipment exceed the 80 decibel (db) level allowed in a plant before hearing protection must be worn. Hearing loss is most often subtle and cumulative. Impairment may not be recognized until it is too late. According to the National Institute of Occupational Safety and Health (NIOSH), noise-induced hearing loss is among the 10 leading causes of work-related illness and injury. Between 1978 and 1987, it was estimated that $835 million was paid in workers' compensation claims for occupational hearing impairment. Effective industrial hearing-loss prevention is an important component of safety-and-health management. The OSHA Occupational Noise Exposure Standard requires employers to offer audiometric testing, a structured hearing-conservation program and the optional use of hearing protection to all employees who work in environments where the daily time-weighted noise exposures are 85 db or greater. At 90 db or higher, OSHA requires the use of hearing protection and an implementation of feasible engineering controls to reduce the noise.