In charges filed Tuesday, Salt Lake City fire investigators wrote that the worker struck two holes in the gas main outside of a building at the Country Lake Apartments complex, 395 E. Woodlake Drive (4050 South), while he was on a service call Oct. 10 for a leaky gas range.

The worker said he was using a metal prodding bar in the ground near the building to learn whether natural gas was leaking into the soil, when the bar struck the gas line, investigators wrote. The worker then used a shovel to clear the soil off the gas line, when he struck another hole into the line.

"A large 'whoosh' of gas escaped a second breach and ignited spectacularly," investigators wrote.

The break in the line occurred near the building, where pipe was visible without digging, investigators wrote. The worker's actions were not in keeping with safety guidelines of Questar or of the state Office of Pipeline Safety.

The break in the gas line created a "jet of burning natural gas" that reached three stories and caused damage estimated in the "low millions of dollars," investigators wrote.

The worker is charged with causing a catastrophe or, alternatively, reckless burning, both misdemeanors.