At about 11:45 p.m. Wednesday night, 3� hours after the rupture occurred, the Providence Department of Public Safety announced the leak had been shut off. That's when Route 195 was reopened to traffic in both directions. Allens Avenue remained closed into the early morning hours of Thursday.

PROVIDENCE, R.I. — A high-pressure natural gas line near the Manchester Street Power Station ruptured near Franklin Square about 8:15 p.m. Tuesday, closing both directions of Route 195 in Providence, shutting down a section of Allens Avenue and snarling traffic throughout the region for several hours.

At about 11:45 p.m. Wednesday night, 3½ hours after the rupture occurred, the Providence Department of Public Safety announced the leak had been shut off. That's when Route 195 was reopened to traffic in both directions. Allens Avenue remained closed into the early morning hours of Thursday.

The break in the underground pipe caused havoc for a large portion of Wednesday night. Frustrated motorists were forced to take detours off a jammed Route 195 and National Grid workers scrambled to shut down the gas, which was escaping with such force that witnesses said it sounded like a jet engine. The roar continued for several hours.

The cause of the rupture of one of the primary natural gas supply lines into Providence was believed to involve an equipment malfunction. There were no further details Wednesday night. A National Grid representative at the scene said that gas service to other customers will not be affected with the line completely shut down to deal with the rupture.

Pare said there were no injuries. Emergency vehicles swarmed to the area near the Providence River. Two businesses near the rupture were evacuated.

After the rupture occurred, witnesses reported hearing a loud, ongoing roar in the area and seeing a haze over Route 195.

"It's highly explosive," Pare said of the gas at about 9:35 p.m. "We don't want that to be ignited."

Danielle Williamson, a spokeswoman for National Grid, said the leak occurred in a steel pipe on National Grid property at Franklin Square. That's where the utility has a "take station," where the gas under high pressure for transmission over long distances is reduced to a lower pressure for distribution to homes and businesses.

A Providence Fire Department official said the gas in the line is at a pressure of between 200 and 300 pounds per square inch.

Williamson said National Grid got its first call about an odor at 8:13, and technicians arrived at 8:39 p.m.

She saw a sudden jump in calls reporting the odor of gas at around 8:35 p.m.

Police Lt. George Smith said ambulances headed from other areas to Rhode Island Hospital were diverted to other hospitals because of the road closures.