Expert tells West Roxbury residents they don't want to be around if a proposed natural-gas facility blows up

Residents already inured to explosions at the West Roxbury quarry gathered tonight to get scared even more by the high-pressure natural-gas line planned for Grove and Centre streets along one side of the quarry - and the proposed transfer station across the street from it that would feed the out-of-state gas into National Grid's Boston-area distribution system.

Mark McDonald of NatGas Consulting in Hyde Park told residents at a meeting at the Irish Social Club that such transfer stations are usually placed in remote areas, not densely populated neighborhoods - and especially not right across the street from an active quarry that does lots of blasting.

McDonald said the "metering and regulating" transfer station, which he said would generate a hissing sound 24 hours a day , would step down the 750 lbs. of pressure from a large main to 100 or 150 lbs. of pressure in National Grid pipes. Typical pressure for a gas line into an individual house is a quarter of a pound, he said.

Its proposed location is on currently wooded land off Grove, just south of where Centre splits off. The pipeline would pass within a a couple hundred feet of the Beethoven and Kilmer schools and the Deutsches Altenheim nursing home.

McDonald pointed to a 2010 gas-pipeline explosion in a residential area in San Bruno, CA as an example of what could happen in West Roxbury: The explosion leveled 38 houses, killed eight and created a 40-foot-deep crater.

McDonald said he worries about the risk of contractors on other projects inadvertently puncturing the main. "When you dig and hit a 750-lb. line, you have a real problem." Even terrorism could be an issue - he said somebody with basic knowledge of gas lines could wreak havoc with "a couple of turns of a wrench" at the transfer station, sending highly pressurized gas down National Grid mains not designed for the load.

He added that he gas in the large main would have no odor - that's only added at the National Grid end - so residents wouldn't even be able to tell if the new main were leaking from the cracks that might be caused by vibrations from blasting at the quarry.

"This pipeline does not belong in this neighborhood, and the gas companies and the regulators know it," he said. But regulators, he said, are reluctant to go against the energy companies. He noted that FERC Chairwoman Cheryl LaFleur - herself from the Boston area - took the job after serving as executive vice president and acting CEO of National Grid.

Spectra Energy says the new pipeline, which would run from Westwood through Dedham and into West Roxbury by way of Washington Street and up Grove, will increase the supply of natural gas in the region and help National Grid better regulate gas pressure in its mains. And it says the pipeline will run mostly under parking lots and roads, is completely safe.

The Federal Energy Regulatory Commission has final say over the project; a decision could come in mid-January. After listening to McDonald, the roughly 40 residents split up into smaller action groups to plan quick action to try to stop the pipepline - from letter writing campaigns to possible street protests.

Organizers put special emphasis on contacting senators Warren and Markey. Unlike Mayor Walsh, US Rep. Steve Lynch, state Rep. Ed Coppinger and City Councilor Matt O'Malley, all of whom oppose the pipeline, the two senators have yet to say how they feel about it one way or the other.