State environmental officials have been responding to complaints about dust from demolition that is making way for the City Creek Center and so far have not found any violations of air-quality rules, a manager for the Utah Division of Air Quality said Wednesday.

However, a group of local physicians says that state regulations are not sufficient to protect the public from such activities, and demolition dust and the implosion early Saturday morning of the former Key Bank tower at 50 S. Main Street could pose a danger to the public.

The Crossroads and ZCMI Center malls are being demolished to make way for the 20-acre City Creek Center, a mixed-use development that will cover two blocks of downtown Salt Lake City. The project is being carried out by contractors for The Church of Jesus Christ of Latter-day Saints.

Dale Bills, spokesman for City Creek Center, said, "We are working in compliance with air quality standards and will continue to use all practical means to control dust."

A City Creek Center spokeswoman said Wednesday that project officials have not received any complaints about the dust, and safeguards are in place to protect the public when a large building is imploded.

For many days in recent weeks, voluminous plumes of dust from the demolition have billowed into the air on the ZCMI Center block. Workers often wet down surfaces with a fire hose in an attempt to control the dust.

Bryce C. Bird, air-standards branch manager for the Utah Division of Air Quality, said most of the complaints his agency has received stem from mud tracked out from the project to the street, where it dries and is kicked up by vehicles.

"We have received complaints, and throughout this project, we've had inspectors" who look at the site or respond to complaints, he said.

The dust on site is monitored, and dust leaving the property is not supposed to obscure a contrasting background by more than 10 percent when seen with the sun at an angle behind the observer, he said. The contrast is averaged over six minutes.

"Our inspectors have been down there, have done opacity readings but have not observed any violations of that rule," he said.

Even so, Bird said, he has discussed the dust complaints with the contractors: "I've talked to them and encouraged them to keep up the measures to control the dust."

The contractor has developed a dust-control plan that includes the use of water, as well as gravel pads at the site's exits to catch dirt, he said.

Okland Construction went to the Utah Air Quality Board in May and received a variance from the usual dust opacity rules for Saturday's implosion. Bird said the exception was granted because there was no practical way to control dust from the implosion.