Misuse of noisy toys, such as the High School Musical Rockerz Jammin Guitar and the Cheetah Girls In Concert Collection Doll, can lead to a lifetime of hearing loss for children, a new study warns.

Children may be clamoring for a Hannah Montana – In Concert Collection Doll or a new Tickle Me Elmo this holiday season, but researchers from the University of California Irvine warn that parents should monitor use of these products to ensure children are not holding them too close to their ears.

For their study, researchers tested the loudness of a several toys and found that a number of them reach decibel levels of 100 or more, equivalent to the sound of a power saw, subway train or power mower.

This doesn’t make these toys unsafe, they said. But many of the toys emit sounds at decibel levels high enough to cause permanent hearing damage if not used properly.

“All the toys we tested are safe when used as they are designed,” said Jeff Carroll, graduate researcher in biomedical engineering who tested 17 toys, in a statement. “But kids don’t always use toys as they were designed. So it’s advisable for parents to offer greater guidance for their proper and safe use.”

The High School Musical Rockerz Jammin Guitar, which is recommended for children ages 3 and up, topped the list of toys at 106 decibels, followed by the Cheetah Girls In Concert Collection Doll at 04 decibels. Sound levels were measured approximately one inch from the speaker on each device, much closer than they should be used.

Prolonged exposure to loud sound can cause permanent hearing damage, according to Occupational Safety and Health Administration and the National Institute of Occupational Safety and Health. OSHA considers it safe to listen to a 100 decibel sound for up to two hours a day, while NIOSH recommends less than 10 minutes daily for the same sound.

Both Fischer Price and Disney, makers of many of the toys tested, said their toys are safe, according to a report from ABC7 Los Angeles. Fischer Price also said comparing their toys to OSHA standards is misleading, since their guidelines assume sustained exposure.

Researchers concluded from the study that parents should make sure children keep "noisy" toys or devices at a reasonable distance from their ears, and make sure they're not used for prolonged time periods.

“Children are very sensitive to toys and other devices that emit loud and high pitch sounds or that rely on earphones. The hearing loss from noise damage is permanent and currently is not curable,” said Dr. Hamid Djalilian, an assistant professor of otolaryngology who treats and studies hearing disorders, in a news release.

Toys Sampled: Decibel Level

High School Musical Rockerz Jammin Guitar: 106

Cheetah Girls – In Concert Collection Doll: 104

Hannah Montana – In Concert Collection Doll: 103

VTech V.Smile Baby: 103

CAT Motorized Dump Truck: 102

Tickle Me Elmo: 100

Transformers Trans-portable Activity Center: 99

Tonka Lights and Sounds Hummer: 97

Bob the Builder Deluxe Talking Tool Belt: 96

Bosch Toy Chainsaw: 95

Tickle Me Cookie Monster: 94

Little People Dump Truck: 92

Cabbage Patch Kids Babies: 91

Leap Frog Learning Lily: 90

Tickle Me Ernie: 90

Playskool Gloworm: 85

Little People School Bus: 80