If Stericycle's medical waste incinerator in North Salt Lake ever emitted pollution levels beyond standards designed to protect human health, then Utah Division of Air Quality officials say they would send out a notice.

Despite the lack of any such alerts after years of keeping a close watch on Stericycle, residents are still concerned as the company's five-year permit renewal comes up for public discussion.

North Salt Lake resident Andrea Seminario has two children attending a school near the incinerator, which emits lead, mercury and dioxin at what the state says are low or safe levels, even during incidents when pollution-control equipment is bypassed.

"Who wants to have their children go to school nearby where that's happening?" Seminario asked in an interview. "It's just not healthy."

Seminario, who had asthma before moving to North Salt Lake five years ago, said she and her husband have talked about moving. She said her own respiratory condition is made worse by the overall air quality in her neighborhood, impacted by multiple factors. Her children's health, she said, is fine.

Stericycle's Selin Hoboy said Friday in an e-mail response to questions from the Deseret News that the North Salt Lake facility, which it acquired in 1999, is state-of-the-art, clean, safe and well-run and that emotional issues such as these may be driven by people's unfamiliarity with the technology and subject matter involved.

"In the entire history that Stericycle has owned and operated the North Salt Lake facility, we have never had a single emissions or air-quality-related violation of any kind whatsoever," said Hoboy, vice president over environmental safety and health. "We are very proud of the facility's outstanding operating record."

To state regulators, Stericycle is a minor player on the pollution stage.

"They're a pretty small emitter," said Regg Olsen, a permitting manager for DAQ.

Olsen points out a bigger potential air quality concern to the north, where a row of oil refineries releases more pollutants into the air on a daily basis than Stericycle. He also noted how rigorous air quality standards developed by scientists for the federal Environmental Protection Agency are sufficient to be applied to companies like Stericycle.

"They do have an impact, there's no question about that," Olsen said about Stericycle. "If you look at it in the context of what is going on in the air shed, it's probably not very significant."

DAQ director Cheryl Heying said that much of the area around Stericycle is industrial, with a sand and gravel operation, refineries and lots of traffic from I-15 and I-215. But it's also where Woodside Homes developed the Foxboro subdivision, where residents have said fouled air is affecting their children.