Millcreek, UT – A 12-unit apartment building was destroyed Tuesday when a Questar natural gas line exploded while a worker was investigating complaints of a leak.

The 5:30 p.m. explosion immediately spread flames to a housing unit at the Country Lake Apartments complex at 364 E. Woodlake Cove (4095 South). It knocked the worker back, but he jumped up and ran into the building to evacuate residents, said Questar spokesman Darren Shepherd. All occupants were able to escape safely.

Firefighters from the Unified Fire Authority and other local departments extinguished the fire in the building within 30 minutes. But flames fueled by the continuing gas leak shot into the sky and sent billowing gray smoke into the Salt Lake Valley for almost two hours. Meanwhile, firefighters worked to contain the fire and protect surrounding buildings.

“The explosion came, and I didn’t know what to do,” said Charmaine Harmon, an 18-year-old resident of the apartment closest to the flames. “I just ran out the balcony.

“Then the Questar guy came to get me. He shielded me from the flames. … As far as I’m concerned, he saved me.”

Three men who lived in the complex also assisted in knocking on doors and helping people out, said Gavin Nuffer, one of the men. They had been worried that children who lived in an upstairs unit were trapped inside, but the family was soon located safely outside.

The only person hurt during the fire was an onlooker trying to climb a fence, said Unified Fire Authority Capt. Jay Torgersen. The man fell and twisted his ankle.

Firefighters allowed the fire to continue burning until Questar crews shut off the gas line because letting it burn was safer than allowing dangerous gas to remain in the air.

“This way, it’s contained,” Torgersen said.

Using a bulldozer and several jackhammers, crews located the plastic underground line and pinched it off in two places by 7:15 p.m. The flames then quickly died.

Investigations into the fire and its cause will be done by numerous fire departments and by Questar, the agencies’ respective officials said. Part of the inspection will include ensuring that gas lines in the rest of the large complex are safe and working properly.

Without such an investigation, apartment complex resident Eric Caruso said he would consider leaving the area. His unit was not in the destroyed building.

“I’ll definitely have a talk with management,” said Caruso, among dozens of Country Lake residents who gathered to watch the blaze. “I expect a complete check — at a minimum.”

The Alliance Residential Co. manages the complex, which was built in 1975. Alliance is a Phoenix-based organization with more than 100 complexes nationwide and at least six in Utah. Representatives would not comment Tuesday night but promised someone with the company would talk with news media soon. Fire officials estimated damage at $2.5 million. All residents displaced by the fire were relocated to vacant units within the complex.

Nuffer and a friend, Shawn Hayes, said they believe the fire was caused by the Questar worker. Shepherd said Tuesday night there was no way to know whether that was the case. Many things, such as cell phones or friction, could have sparked the highly volatile gas, he said.

The explosion was the second in Utah this year that occurred while a worker was investigating a gas leak. The first happened Feb. 6 in Saratoga Springs and killed a woman, the worker and injured an 18-month-old girl. It destroyed the home.

Shepherd said Questar has an evacuation plan for dangerous situations. Tuesday, the procedure was followed, he said.

Residents should immediately call Questar any time they smell natural gas, he added. They should then try to get everyone out of the area until Questar deems it safe. The company’s emergency toll-free service number is 1-800-541-2824.