A new study has found that noise making machines meant to soothe babies into sleep may actually be damaging for their hearing in the long run.

According to CNN, the study, published in the journal Pediatrics, says some machines can be turned up loud enough to be able to damage an adult's hearing. The machines can be used to cancel out external noises like sirens or household chatter, but if turned up too loud, it could leave lasting effects.

"These machines are capable of delivering enough of a dose over a period of time to theoretically cause hearing loss, but that's not been tested," study senior author Dr. Blake Papsin, a researcher with the University of Toronto and the city's Hospital for Sick Children, told CNN.

While experts have not agreed on a recommendation for parents who use these machines, the study was aimed to measure the effect on the effect the maximum volume has on an infant. The study researchers tested the volume level at distances of 30, 100 and 200 centimeters. 30 centimeters was from the baby's head to the crib's rail. 100 centimeters was near the crib and 200 centimeters was across the room.

Patti Martin, director of audiology and speech pathology at Arkansas Children's Hospital in Little Rock, told WebMD the best practice for parents would be to place the sound machine across the room.

"If you choose to use them, just be cautious," said Martin, who was not involved with the study. "Don't place them right on the railing of the crib. Put them across the room."

Papsin said there is evidence to suggest that some parents are using these sound machines too much and for too long. For example, he said some parenting advice sites say to leave the machine on all night and loud enough to cancel out other external noises.

"So some parents are probably overexposing their babies to noise," Papsin told WebMD.

He also told the Huffington Post that the noise itself, white noise, produced by these machines is not the best solution. He said classical music is more complex and better to cancel out other sounds.

"I'm not going to say don't use these... but if you are going to, use it cautiously," he said. "Me personally? I wouldn't."