Can MP3 Players cause Hearing Loss?

I just attended a lecture by Dr. Billy Martin of Oregon Health Sciences University.
He is concerned that a generation of children who are losing their hearing at an early age. Parents beware! Monitor volumes and teach your children ear safety. Headphones seem to invite people to turn up the volume and the small hairs in our inner ear cannot survive with continuous abuse. There is a relationship to volume and length of time you are exposed. The rule of thumb is to moderate the volume or not use headphones for more than an hour at a time. The second rule is to not have volumes over 85 decibels. For comparison: a humming refrigerator is 45 decibels; voice communication is 60 decibels; motorcycles, firecrackers, firearms are over 85 decibels. Avoid noises that are too loud, too close, or last too long. For more information go to the National Institute on Deafness and other Communication Disorders.