ISO estimates of noise-induced hearing impairment.

The revision of International Organization for Standardization (ISO) standard ISO 1999 [(1971). International Organization of Standardization, Geneva, Switzerland)] in 1990 was based on two noise and hearing study databases, one presented by Burns and Robinson [(1970). Hearing and Noise in Industry (Her Majesty's Stationary Office, London)] and the other by Passchier-Vermeer [(1968).