COLUMBIA, Mo. – One of spring’s routine home maintenance jobs—tree trimming—can quickly cut your ability to hear.

It takes less than 30 minutes of operating a chain saw without hearing protection to cause permanent damage, says Bob Schultheis, University of Missouri Extension natural resource engineering specialist.

“Nothing can restore lost hearing,” says Karen Funkenbusch, MU Extension state safety and health specialist and director of the Missouri AgrAbility Project. “Once it’s gone, it’s gone! But hearing loss caused by noise is preventable.”

Noise from a chain saw can be more damaging than noise from a tractor and only slightly less damaging than an ambulance siren or jet airplane. That’s why it is important to wear hearing protection when operating a chain saw, Schultheis says.

Acoustic earmuffs work best in preventing hearing loss and reducing stress, anxiety and fatigue, Funkenbusch says. Another option is rubber or foam earplugs, but they aren’t as effective. Ear protection devices only block out sounds that are dangerous to hearing, and can reduce noise levels by 15 to 40 decibels. Cotton is not effective at reducing noise exposure.

Funkenbusch recommends that farmers and people working in their yards keep a pair of earplugs in their pockets at all time. “The easier they are to use, the more likely you will use them,” she says.

To reduce noise levels, keep machine parts well lubricated, replace worn or unbalanced parts that cause vibration, and use high-quality mufflers on engine-powered equipment.

Your body has built-in warnings against hearing loss, including temporary hearing loss and tinnitus, or ringing of the ears. See your doctor if either condition occurs.

“As a rule of thumb, if you need to raise your voice to be heard an arm’s length away, the noise is loud enough to damage your hearing,” said Schultheis.

Hearing protection is just one of the safety measures Schultheis recommends to utility workers attending MU Extension chain saw safety classes. He also recommends that chain saw users invest in protective clothing.

Ballistic nylon chaps and vests prevent injury from chain saw teeth. Although chaps cost about $80 and the vest costs about $100, they are a bargain compared to the cost of an emergency room visit.

A hard hat, safety goggles or glasses, and safety boots or shoes are as important as your choice in chain saw, Schultheis says. Wear ballistic nylon or leather gloves, and never wear tennis shoes when working with a chain saw.

Chain saws cause more than 40,000 injuries in the U.S. each year. The average chain saw injury requires 110 stitches with the average medical bill estimated at $20,700 in 2015.

Learn more about the dangers of noise from MU Extension guide G1962, “Noise: The Invisible Hazard,” available from county MU Extension centers and online at https://extension.missouri.edu/g1962. Or contact Funkenbusch at the Missouri AgrAbility Project, 800-995-8503.