While Berkshire Gas Co. claims to have one of the "tightest" distribution systems in Massachusetts, there are leaks.

At The Eagle's request, Berkshire Gas provided the number of leaks in each of the 12 Berkshire County towns that have them, updated as of Aug. 31.

North Adams, Adams, Pittsfield and Williamstown have the most leaks. And 49 of the county's 248 total leaks are classified as Grade 2, a status listed as nonhazardous at the time of detection but which require "scheduled repair based on probable future hazard," and repair or replacement within 12 months.

An additional 199 leaks are rated Grade 3. That category is considered nonhazardous, but leaks must be re-evaluated during the next scheduled survey, or within 12 months from the date last evaluated, whichever comes first.

None of the leaks is Grade 1, the category that requires immediate repair.

Spokesman Christopher Farrell said leaks are monitored with truck-mounted detection systems, as well as with hand-held detectors used to pinpoint leaks around sidewalks and public buildings.

As it decides which old pipeline sections to replace, Berkshire Gas considers leak-prone pipes as well as "operational considerations."

Pittsfield has the most leaks in the Berkshires — a total of 86, 24 of which are Grade 2.

Pittsfield Fire Chief Robert Czerwinski said he knows where all the leaks are and said his department works closely with Berkshire Gas.

"We're on a first-name basis with most of their street people," he said. "At any fire we have, they dispatch a crew."

Czerwinski said the most common gas-related incidents the department faces come when contractors hit a pipe during construction — not leaks from corroded pipes. Another concern in the city are amateur gas line hookups that don't meet code, he said.

"Years ago, gas employees warned us that people would build onto their existing home system," Czerwinski said. "There are so many pipes that Berkshire Gas might not even be aware of. Somebody may have a gas line in their home and later change [it] from an oil burner to gas furnace, and they had some buddy of theirs tap into their gas line."

By law, the company must notify municipal fire departments about the location of leaks, said Great Barrington Fire Chief Charles Burger, who also said fire crews are trained for gas-related fires and explosions.

"Often, we're notified first because someone smells the leak even before Berkshire Gas gets here," he said.

Great Barrington has six known leaks, according to Berkshire Gas. These are all Grade 3, meaning they are considered nonhazardous, but state law requires that they be re-evaluated "during the next scheduled survey, or within 12 months from the date last evaluated, whichever occurs first, until the leak is eliminated or the main is replaced."

A 2014 investigation by USA Today took a close look at gas leaks.

"About every other day over the past decade, a gas leak in the United States has destroyed property, hurt someone or killed someone," the report says. "The most destructive blasts have killed at least 135 people, injured 600 and caused $2 billion in damages since 2004."

Apart from the potential safety hazards, leaks also waste ratepayer money and cause unburned methane, or "lost gas," to be released into soil and into the atmosphere, where it contributes to greenhouse gases.

Gas companies have to report leak data to the state Department of Utilities. With this information, one Cambridge nonprofit, Home Energy Efficiency Team, has created an interactive map with addresses for repaired and unrepaired leaks in more than 200 towns and cities in the state as of Dec. 31 of each year.

It might be that no leak should be left alone. The Boston Globe reported in 2016 that these leak ratings might not be accurate.

Boston University researchers, measuring gas from distribution system leaks in the Boston area, had "found little difference between the dangers of so-called Grade 1 leaks, which utilities are obliged to fix immediately, and Grade 3 leaks."

"Even small leaks can pose a serious risk of explosion," researcher Margaret Hendrick told The Globe.

Given the recent explosions in the Merrimack Valley, state Sen. Adam Hinds, D-Pittsfield, suggested that oversight hearings might be on the agenda soon, based on the National Transportation Safety Board's final report.

And Hinds said he was "shocked" to hear charges that the DPU might be understaffed — a reference to criticism unleashed at a recent news conference by Jay Gonzalez, a Democrat running for Massachusetts governor. Gonzalez said there are eight DPU inspectors to monitor 21,000 miles of natural gas pipeline. He said that, if elected, he would hire more.

Gov. Charlie Baker confirmed that the DPU has eight inspectors but said three more will be added.

Hinds said the staffing question will be debated.

"A lot of us will be trying to unpack what resources are needed," he said.

Heather Bellow can be reached at hbellow@berkshireeagle.com or on Twitter @BE_hbellow and 413-329-6871.