Workers with hearing loss face additional risk factors on the job site such as an inability to hear warning signals or alarms, an increased difficulty to tell where sounds are coming from, and increased difficulty communicating with co-workers. This occurs due to the "hearing protection device (HPD)" attenuating the signals/noises below the level that the worker is able to hear. OSHA regulations require individuals to wear HPD regardless of their amount of hearing loss, even if they have a severe to profound hearing loss. Workers that have sustained a standard threshold shift are required by OSHA to wear HPD at an 85 dB TWA. There are special considerations to take into account when fitting HPD on workers with a hearing loss. These factors include comfort, degree and configuration of the worker's hearing loss, the necessary communication demands in the workplace (verbal vs. nonverbal), the ease of communication, and the noise exposure levels of the worker.