Federal investigators pinpoint what caused string of Massachusetts gas explosions [View all]

On an afternoon last September, a string of explosions suddenly hit Merrimack Valley, Mass. At least five homes were destroyed and a person was killed. More than 20 others were injured.

Federal investigators say they have now pinpointed what caused the sudden explosions on Sept. 13 — a natural gas company field engineer made a major mistake in the plans he developed for construction work that happened earlier that day, resulting in a disastrous chain reaction.

After the incident, authorities immediately suggested it was caused by a problem with the natural gas distribution system, ultimately resulting in damage to some 131 structures.

In the Safety Recommendation Report released Wednesday by the National Transportation Safety Board, investigators found that on the day of the explosions, Columbia Gas of Massachusetts had been in the process of installing a new plastic distribution main to replace an old cast-iron one.

But, according to the report, the crew abandoned the old main with regulator-sensing lines still in it. The regulator-sensing lines were part of a system that controlled the gas network's pressure.

At: https://www.npr.org/2018/11/16/668612558/federal-investigators-pinpoint-what-caused-string-of-gas-explosions-in-mass?utm_source=facebook.com&utm_medium=social&utm_campaign=npr&utm_term=nprnews&utm_content=2045&fbclid=IwAR2tmycM0LcnMb5-QYJkyx7GPXQ1kJN0By55b0OKUewfdc6I1qfmQ0VqiYo