Acute hearing impairment by extremely high sound pressure levels

The bulletin for occupational disease no. 2301 in the annex of the Occupational Disease Act, noise-induced hearing impairment, ("Merkblatt zu der Berufskrankheit Nr. 2301 der Anlage zur Berufskrankheiten-Verordnung: Larmschwerhorigkeit") states that sound events with an intensity exceeding 137 dB (C) may cause immediate mechanical damage to the inner ear. Up to now a distinction has been made between prevention and actual damage potential for the risks caused by sounds with extremely high peak levels. In the field of prevention the unweighted sound pressure peak level of 140 dB, which is now 137 dB(C,peak) according to the LarmVibrationsArbSchV, was applied as the trigger threshold for measures; in contrast actual hearing impairment was not found until150-160 dB. This article compiles the current state of knowledge and demonstrates that in the area of the reasons mentioned here for acute hearing impairment, no scientifically based new findings exist especially with reference to publications listed in the bulletin.