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Nearly four hours after a five-alarm fire erupted Friday at an automobile scrap yard in west Salt Lake City, 100 firefighters had fully contained it, along with a subsequent grass fire ignited nearby — blazes which forced a two-and-a-half hour closure of Interstate 80 as thick, dark smoke blew across the freeway.

Salt Lake City fire officials said just before 4 p.m. that both fires were fully contained, though still active. Fire officials estimated the scrap yard blaze affected at least half of the nine-acre property located near 4400 West and 700 South, and had burned about 50 acres.

The fire was caused by sparks from a worker cutting pallets, Capt. Mark Bednarik said.

Interstate 80 was reopened about 4 p.m., about two-and-a-half hours after the Utah Department of Transportation closed the freeway in both directions from 5600 West to the interchange with Interstate-215.

Many drivers who were in the area at the time of the closure found themselves stuck in grid-locked traffic for more than two hours.

The fire, first reported a few minutes after noon, sent huge plumes of smoke into the sky as it burned buildings, pallets, vehicles, tires and other materials at Rio's Auto Recycling, a commercial storage yard at 4385 W. 700 South, fire officials said.

Two shop-type buildings at the site were ruled complete losses, Bednarik said. The roof of a building with cinderblock walls had caved in, and the other building, made of metal, was reportedly on the ground.

Fire officials originally believed hazardous materials were responsible for periodic explosions which sent balls of orange flames into the air that could be seen and heard at least five miles away in downtown Salt Lake City.

But the property owner told officials that the only hazardous materials he knew of were propane bottles for fork lifts and any residual flammables inside cars on site, Bednarik said.

The fire was started by a scrap yard worker who had been cutting pallets earlier in the day, which produced small sparks, fire officials said. The man believed he had extinguished all the small fires from the sparks and went to lunch. But when he returned, he found an active fire that was too big for him to control, officials said.

Shortly after 1 p.m., flames from the original blaze jumped 700 South, sparking a grass fire that headed toward — and eventually reached — I-80.

The grass fire had threatened a power substation and a Union Pacific rail line near 4800 West and 700 South, but Salt Lake City Fire spokesman Jasen Asay said firefighters prevented the fire from reaching them.

One firefighter suffered minor injuries from heat exhaustion while fighting the blaze, Asay said.

Salt Lake International Airport spokeswoman Nancy Volmer said the smoke never interrupted operations at the facility Friday afternoon.

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