Hearing protection devices are worn on or in your ears to protect against hearing loss in environments with potentially hazardous noise levels. These protective ear muffs or ear plugs typically have a noise reduction rating (NRR) specifying the decibels (dB), or sound intensity, by which they reduce sound levels. OSHA standards call for hearing protectors that reduce exposure to below 85 dB over the course of an average 8-hour work shift to avoid noise-induced hearing loss (NIHL). Hearing protection is commonly used wherever loud machinery is being operated such as at factories, mills, mines, construction sites, landscaping operations, and medical testing facilities.