Urgent necessity of vast improvements are needed at least in the form of "Hearing Fit Check" science to the Appendix B of CFR 29, 19.10.95 Fit Check testing for hearing is as important as respiratory fit check testing is Law.
This past year I used a field fit check system(technology won the "Anwar-Bullard" science award for innovation). meeting ANSI ambient sound standards level at 1000 hz and above in the field(forestry), half of our participants were tested indoors meeting the ANSI std unequivocally. The testing: occluded/unoccluded, ear plugs, ear muffs, to effectively train proper wearing or fit with best evidence practices in action. This led to better hearing protection device (HPD) choices and removal of inferior protection devices.
We utilized 7 frequencies to gain an accurate representation of the hazard noise exposures of 100+ decibels our employees are exposed to. Our Hearing Conservation Plan of baseline audiogram testing validated improvements over the past 3 years.
I have inquired about in-ear dosimetry and the commercial technology is new and expensive considering it's availability to the general public. We found the field fit check system to be very economical, educational, and effective in preventing hearing loss for our 100 + employees. It seems very obvious that the requirement to have employees who are subjugated to noise hazard injury must be protected from losing an important sensory organ. Hearing loss continues to be a very damaging obscured injury and very similar to MSD's in the much touted modern world we inhabit