Utah's top air-quality official says a cloud of acidic pollution released by Kennecott across the I-80 freeway Sunday night may not have caused lasting harm - but anyone who drove through it and has questions should contact his doctor.

Burnell Cordner, director of the Utah Air Bureau of Air Quality, added that this potential danger might point out the need to modify the law. Possibly, an emergency-response plan might need to be put into effect.Kennecott had a power outage Sunday night that affected the copper company's No. 8 acid plant at the Magna smelter, he said.

"When they brought the acid plant back on line, they had a fan failure." The fan whisks pollutants up the company's tall stack. When it failed, a dense mist erupted from a lower level, rather than from stack top.

For a period - Cordner doesn't know how long, but believes it might have been as much as three hours - "there was a fog, I guess, that went north from the plant across the interstate."

Vehicles drove through the acid fog on I-80. The Utah Highway Patrol and Salt Lake County Sheriff's Department directed traffic through the dense murk.

Some drivers and passengers experienced respiratory problems, and "Kennecott had some of them go and get examined," Cordner said.

The mist contained sulfur dioxide and sulfur trioxide. The latter is an acid mist that causes burning sensations in the lungs and throat. At a single dose, it is not likely to cause damage.

Kennecott monitors found sulfur trioxide levels at 1 part per million, Cordner said. The federal limit for the workplace is 2 ppm.

Salt Lake City-County Health Department experts were sent to the scene to sample the cloud. So far, he said, the state has not had a report from the county.

The Deseret News attempted to get comments from Kennecott's environmental experts, but by press time they were not available.