I was told you can damage your hearing if exposure to low levels, is prolonnged.99 db is 1 hour max
102 db is 30 minutes max
105 db is 15 minutes max
108 db is 7.5 minutes max
111 db is 3.75 minutes max
the resulting damage from over-exposure is not immediately apparent as it affects only the higher frequencies.Victims can hear low pitched sounds as well as before, but lose the highs.