Tinnitus masker issues associated with use of tinnitus maskers: the "safe" level of continuous sound depends on the duration of the sound. For maskers worn continuously, or most of the day, a safe level is no more than 70db, in accordance with EPA maximum safe exposure level for 24-hour environmental sound. Maskers louder than 45db or so (the ambient background level of an average home living area) may start to interfere with understanding conversation (about 60db). Masking of high frequency tinnitus (>6,000hz) is difficult because of the resonance characteristics of the human ear as well as high frequency limitations of in-ear devices.
Firefighter lasting affects on the brain. A 2014 report from the National Fallen Firefighters Foundation found that a fire department is three times more likely to experience a suicide in a given year than a line-of-duty death. Mental stress of the job can lead to substance abuse and alcohol abuse as ways of coping with the stress. Another long-term risk factor from firefighting is exposure to high levels of sound, which can cause noise-induced hearing loss (NIHL) and tinnitus. NIHL affects sound frequencies between 3,000 and 6,000 Hertz first, then with more frequent exposure, will spread to more frequencies. Many consonants