Very interesting. It's a long time since I did any hearing and noise exposure work, but I wondered whether they had published or done any further work? For instance, did they have any dosimeter studies of the equivalent 8-hour exposure? A Canadian study in an orchestra pit found that exposures stayed below a safe limit of 87dB(A) 8hr-LEQ, IIRC. Peak measurements are interesting but not necessarily a good guide to hearing damage unless very high impulses.