Any more than five hours of loud music through headphones has the potential to cause permanent hearing loss, according to a study done for the European Commission, the European Union's executive arm.

The study said that children and teenagers need to be protected from "leisure noise." Loud mobile phones were also criticized.

"There has been increasing concern about exposure from the new generation of personal music players which can reproduce sounds at very high volumes without loss of quality," the Commission said in a statement.

Young people pose special risk

Experts estimated that between 50 and 100 million Europeans listen to portable music players on a daily basis. If those players are cranked up to more than 89 decibels for five hours a week, the resulting noise would exceed EU limits for workplace noise. If listened to for longer periods, hearing damage is a concern.

Between 5 and 10 percent of listeners -- 10 million Europeans -- are in danger of having hearing loss, according to the study.

"I am concerned that so many young people ... who are frequent users of personal music players and mobile phones at high acoustic levels, may be unknowingly damaging their hearing irrevocably," Meglena Kuneva, the EU's consumer affairs commissioner, said in the statement.