A refrigeration leak that forced the evacuation of a Kearns manufacturing plant Wednesday morning ultimately led to a bigger problem when a vat of solvents became highly toxic after the vat's refrigeration unit was shut down.

Fifteen employees of SPS Technologies, 4700 S. 5195 West, were taken to Pioneer Valley Hospital for treatment of asthma-like respiratory distress after the refrigeration unit leaked a Freon odorant, said hospital spokesman John Goates.The 15 workers were tested for chemical poisoning and released, and the company was open for business Thursday.

When the refrigeration unit was turned off after the leak was discovered about 9:30 a.m., a vat holding about 100 gallons of Freon-based solvent - used to clean titanium fasteners manufactured at the plant - began to warm up.

The warming set off a chemical reaction that ultimately brought at least 50 firefighters and law enforcement officers to the scene and prompted a call to an East Coast team of chemical experts for help, said Lt. Dennis Steadman of the Salt Lake County Fire Department.

No one was injured in the incident. None of the residents who live near the Kearns plant was in danger nor were there ever any plans to evacuate them from their homes, Steadman said.

By midnight, the firefighters on the hazardous materials response team had tamed the vat of solvents, which over the day was undergoing chemical changes into hydrogen fluoride.

This highly toxic substance is known as a "bone-seeker" because it damages calcium - bone - if it is absorbed through the skin, Steadman said. The poison also damages the muscle tissue surrounding bone, and causes severe swelling and pain.

"There is an antidote, and the hospitals were ready with it," Steadman said. As a precaution, the 15 employees who were evacuated were tested for the presence of the chemical in their systems, as were three firefighters and another employee who was not with the first group to go to the hospital, he said.

Because the incident was highly unusual, local hazardous material experts contacted the Chemical Manufacturer's Association, a New Jersey-based emergency response team, for help, Steadman said.

The New Jersey experts had a "moment-by-moment update" on what was happening in Kearns because the chemical reaction was a process occurring over time, and the cleanup team had to be ready to alter its response to the chemical changes, he said.

The experts, reasoning that it was too late to protect the building from any potential contamination, decided that the best way to handle the chemicals was to neutralize them in place with soda ash.

"It was the safest alternative for our people," Steadman said.

The county firefighters received assistance from West Valley and Salt Lake firefighters, as well as the county sheriff's office and experts from the state and county health departments. It took firefighters more than 15 hours to contain the chemicals.

"I felt like we had it under control all day," Steadman said. "It takes all day to cover all the bases."