Investigators are still several weeks away from answers about a natural gas leak explosion that destroyed two Main Street buildings in January, but they are learning more about the history of the gas lines.

The pipe blamed with leaking the gas had not been disturbed for at least 70 years and was possibly much older.

“But I’m not convinced that the age of the pipe is significant,” said Gary Farmer, gas safety manager for the state Public Utilities Commission. “Cast-iron pipes are very long-lived and durable. So we’re not convinced the age of the pipe caused the leak.”

The pipe was part of a section first laid along Main Street in 1895. Parts of that section were updated in 1906 and part was repaired in 1934.

“We don’t know the age of that one piece of pipe,” Farmer said. “We don’t know what parts were updated when, at least not yet.”

Farmer was continuing to review Northern Utilities’ maintenance and testing records Friday. The company owns the natural gas pipeline network under Lewiston.

The records showed that Northern Utilities trucks were looking for leaks along Main Street 10 days before the explosion. The trucks patrol city streets using a device called a flame ionization leak detector to sniff the air, testing for natural gas.

The trucks did not find a leak at that time.

“It doesn’t mean there was no leak,” Farmer said. “It just means there was no leak detected.”

A West Boylston, Mass., metallurgical firm is still testing a 6-foot section of cast-iron pipe removed from Main Street in front of the former Hotel Holly, which burned to the ground soon after the explosion. Lewiston Radiator Works, next to the hotel, also was destroyed.

Farmer doesn’t expect test results for another month.

Fire investigators believe the Jan. 12 explosion was caused by natural gas that leaked from the pipe and seeped into the basement of the old Hotel Holly. Farmer said the leak could have been active months before the explosion. If so, frozen ground would have forced the gas to seep into an opening, possibly in the hotel.

“That’s what we want the testing to turn up, when it occurred and what caused the break,” Farmer said.

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