My false friend AKA as my memory may be in play here but I do not recall having ear defenders when I was groundcrew. If they were available the hazards of the flightline would have mainly precluded their use.
As for the aircrew headsets they had very few noise attenuating properties.
A trial was carried out on noise levels in the Hercules in 1991 by a university team and their report said the noise in the cargo compartment was 'equivalent to being in a loud disco whist a pneumatic drill is operated nearby' ! they also said 'it would not be tolerated in civilian use as a workplace/transport environment, even with the use of ear defenders' ! I flew for 30 years in this environment.
Needless to say nothing was ever done to mitigate this hazard during my time although I understand the 'J' model Hercules crews are issued with noise attenuating headsets.