Like all things, it depends. Here is some information about safe volumes and exposure times:
“Very few documented cases of noise-induced hearing loss are tracked to long-term use of handheld stereos alone, but more research is needed, Fligor says.
Fligor is researching safe-listening levels in MP3s. He and colleagues published a study in 2004 that determined safe-listening levels with portable music players such as the Sony Walkman; the study found that one hour a day at about 60% volume was safe. Preliminary results of the MP3 study show figures in the same ballpark, he says.”
To answer your actual question as posed without the details. No, but I am very worried about what tuning out of real life for hours and hours will do to people and a whole generation. When you have your ear buds in, you cannot hear wind, rain, birds, insects singing, the sound of water or waves. I think the psychological consequences are likely to be much more severe than just the deafness, although that’s not minor either.