But before beginning construction, Legacy Preparatory's board members signed and sent a letter to North Salt Lake, acknowledging that they were building in an industrial area. A second letter was sent to the school's developer, waiving any rights to sue.

"The Board understands and is fully aware of the location of the Treatment Plant and does not intend to bring, and will not bring, any claim against the Treatment Plant for public nuisance, private nuisance, or other similar claims arising out of the Treatment Plant's normal and ordinary operations," the letter said.

While city officials said Stericycle isn't a threat, at least two autism specialists and a handful of parents — including a former school founder — said the location of the two schools is akin to educating children at a "toxic waste dump."

This Tuesday, North Salt Lake resident Crystal Folgmann has scheduled a public meeting to discuss Stericycle and its proximity to the schools and the Foxboro subdivision. The meeting will be at 7 p.m. at Wasatch Peak Academy, 414 Cutler Drive in North Salt Lake. Wasatch Peak is within a mile of Stericycle.

Presenters at the meeting will include school officials and representatives from Stericycle, the Utah Division of Air Quality, the Sierra Club, activist group Greenaction, and possibly the city staff.

Meanwhile, Dr. Bryan Jepson, an autism specialist and former emergency-room doctor, said that while he supports the purpose behind Spectrum Academy, he would never send his child to the school because it's too close to environmental polluters. Jepson was in Park City this past week to speak at the annual conference of the U.S. Autism & Asperger Association.

"I don't know what would be the best place, but if I were to think of the worst, that's about it," said Jepson, who moved from Utah to Texas about six months ago.

Dr. Kenneth P. Stoller, president of the International Hyperbaric Medical Association, who was also at the autism conference in Park City, said he, too, would worry about the school's location: "You don't put the most susceptible members of society into what could be a toxic waste dump."

For Stoller, the biggest concern for parents of autistic children is Stericycle. The plant, which emits far less pollutants than what is allowed under state law, is known to send mercury, lead and dioxin into the air. At least two published studies show that there are more cases of autism in areas that have higher levels of mercury and other heavy metals in the air, Stoller said.

The latest stack tests for Stericycle showed that it emitted about 0.15 mg/dscm of mercury, according to the Utah Division of Air Quality. Under state regulations, the incinerator is allowed to emit 0.55 mg/dscm (or dry standard cubic meter).