Every couple of months researchers sound the alarm that listening to your MP3 player with headphones at high volumes is going to strike you stone cold deaf. The problem is serious enough that Apple even added volume-limiting technology to its iPod line in 2006, so nervous parents can keep the maximum volume their kids can experience to a less dangerous level.

Now a new study appears to offer more cause for concern than ever, saying that listening to an MP3 player at high volume for only five hours a week -- or an hour each workday -- can do permanent damage to your hearing.

The study comes from Europe's Scientific Committee on Emerging and Newly Identified Health Risks, which estimates that up to 10 million European of MP3 player listeners are at risk of permanent hearing loss due to high listening levels. As portable music players continue to be popular and inexpensive gift items, this is a risk that is only going to increase over the next few years. In fact, the risks are likely to increase as audio quality from mobile music players keeps getting better, since better audio may encourage people to listen longer.

The (arguably) good news: While the damage is cumulative and gets worse over time, it doesn't reach critical levels until you've kept up the five-hours-a-week listening for a full five years.

In Europe, music players are currently limited legally to a maximum volume of 100 decibels, but the study notes that 89 decibels is the cutoff point above which damage could occur. To my knowledge, there are no similar rules in place in the U.S. EU activists are now working to lower that maximum.