In the United States, the Occupational Safety and Health Administration (OSHA) describes standards for occupational noise exposure in articles and . OSHA states that an employer must implement hearing conservation programs for employees if the noise level of the workplace is equal to or above 85 dB(A) for an averaged eight-hour time period.  OSHA also states that "exposure to impulsive or impact noise should not exceed 140 dB peak sound pressure level".  The National Institute for Occupational Safety and Health (NIOSH) recommends that all worker exposures to noise should be controlled below a level equivalent to 85 dBA for eight hours to minimize occupational noise induced hearing loss. NIOSH also recommends a 3 dBA exchange rate so that every increase by 3 dBA doubles the amount of the noise and halves the recommended amount of exposure time.  The United States Department of Defense (DoD) instruction 605512 has some differences from OSHA standard, for example, OSHA uses a 5 dB exchange rate and DoD instruction 605512 uses a 3 dB exchange rate.