Under OSHA, employees exposed to more than 85 dB — about as loud as a crowded restaurant — throughout the day must protect employees' hearing and manage their noise, said Rocky Mountain's Leon Pahler, assistant professor in the Department of Family and Preventive Health at the U. If it reaches 90 dB, employers must alter the work environment.

"It's the minimum the employer has to do, but the maximum this division can enforce," said Larry Patrick, Utah Occupational Safety and Health administrator.

There's some debate about where the floor should be set; OSHA uses 85 or 90 dB for different purposes. Audiologists, who care for damaged ears, use 85 dB. And they use 3-dB increments to estimate how long someone can safely be exposed to loud sound.

Based on federal safe-duration standards, people attending a rock concert, which may measure up to around 120 dB, can listen for only a few minutes without hearing protection if they want to keep their ears safe. But the government does not regulate sound levels for the public. OSHA deals only with work sites.

"For individuals and homes and hobbies . . . it's left up to the individual to maybe have an idea of their noise exposure and how to protect themselves," said Pahler. "Do people know when it's noisy? Yes. Do they do anything about it? Probably not."

If you leave a concert with a clogged feeling, muffled sound or ringing, "there's a pretty good chance it's causing damage to the inner ear," audiologist Young said. Some of it may be temporary and will resolve in a day or even weeks. But what's left after 60 days isn't going to get better. And the degree of loss that gets people's attention when they're older is quite likely a matter of a little damage here and there adding up to a life-altering deficit, he said.

People aren't taking many precautions to protect their ears, either.

"It doesn't feel loud to me," said Andrea Webber, driver of the boat that maxed at 95 dB while pulling a skier. "When you're water-skiing, you're only in the boat while it's going, for like, five minutes at a time. You're not always sitting with that noise."

"I think about noise, usually if it feels loud, but I don't really do much about it unless it's extreme," said Jessica Greene, during Fourth of July festivities in Ogden. "I've never left some place because of it."

At the same celebration, a reporter sitting in the stands during the demolition derby tried to strike up a conversation with the woman behind her. "Do you worry about your hearing?" she asked loudly, pointing to her ears. The woman smiled and touched her earrings. "Thanks," she yelled. "My sister made these for me. I love them."