50 Point Explanation
Audiometric
testing must be offered to any mine worker who is exposed to 85dBA.
They can refuse the test if it's not a condition of employment. Testing
does not correct a hearing problem. It mearly measures hearing changes
over time. Data are reported to MSHA by the mine operator only when an
annual hearing test reveal a 25 dB hearing loss as determined by
averaging the results measured at the 2000, 3000, and 4000 hertz levels.