ABSTRACT
According to NIOSH (National Institute for Occupational Safety and Health), the number of workers that are exposed to dangerous occupational noise levels in the US exceed 30 million, and hover around the 500 million all over the world (Arezes & Miguel 2002a, McReynolds 2005). Arezes and Miguel (2002a) estimated about 780 thousand workers in Portugal to have been exposed to occupational noise in the years 1998, 2000 and 2001.
