NTSB: Over­pres­sur­ized lines caused Mass. nat­u­ral gas ex­plo­sions, fires

Con­tract work­ers failed to ac­count for cru­cial sen­sors

Pawtucket Times - - REGION/OBITUARIES -

BOS­TON (AP) — Over-pres­sur­ized nat­u­ral gas lines were the source of deadly ex­plo­sions and fires that rocked com­mu­ni­ties north of Bos­ton last month, the Na­tional Trans­porta­tion Safety Board said Thurs­day.

The five-page, pre­lim­i­nary re­port found that util­ity work­ers con­tracted by Columbia Gas had failed to ac­count for crit­i­cal pres­sure sen­sors as they re­placed cen­tury-old cast-iron pipes in Lawrence on Sept. 13.

That omis­sion caused high-pres­sure gas to flood the neigh­bor­hood's dis­tri­bu­tion sys­tem at ex­ces­sive lev­els, trig­ger­ing more than 80 ex­plo­sions and fires across the city, as well as neigh­bor­ing North An­dover and An­dover.

One per­son was killed and about 25 oth­ers were in­jured in the en­sur­ing chaos. The gas ex­plo­sions also dam­aged 131 struc­tures and de­stroyed five homes. Thou­sands of homes and busi­nesses are still with­out nat­u­ral gas ser­vice as Columbia Gas re­places some 50 miles of gas pipe­line.

The work is about onethird com­plete, and the com­pany says all cus­tomers should have gas ser­vice by

Nov. 19.

Joe Ham­rock, pres­i­dent of NiSource, Columbia Gas' par­ent com­pany, said in a state­ment that it is pro­hib­ited from com­ment or spec­u­lat­ing on the cause of the in­ci­dent un­til the fed­eral in­ves­ti­ga­tion is com­plete.

But he noted that in the hours im­me­di­ately af­ter the in­ci­dent, the util­ity com­pany sus­pended sim­i­lar work else­where and im­proved its pro­ce­dures around low-pres­sure gas sys­tems like the one in Lawrence.

"We saw these as re­spon­si­ble steps to take in the af­ter­math of the in­ci­dent and while the facts were be­ing gath­ered," Ham­rock said.

U.S. Sen. Ed­ward Markey, a Mas­sachusetts Demo­crat, said it's still not clear how Columbia Gas could have al­lowed the disas­ter to hap­pen, whether it could have been pre­vented and whether the com­pany was ad­e­quately pre­pared to re­spond to a disas­ter on that scale.

"The re­lease of the pre­lim­i­nary re­port raises more ques­tions than an­swers," said Markey, who, along with Demo­cratic U.S. Sen. El­iz­a­beth War­ren, has been re­view­ing the com­pany's in­ter­nal pro­ce­dures fol­low­ing the ex­plo­sions.

The Na­tional Trans­porta­tion Safety Board, in its re­port, says the disas­ter was rooted in fail­ures at the plan­ning stages of the Lawrence pipe­line project, which was de­vel­oped and ap­proved by Columbia Gas.

The agency said the work pack­age didn't ac­count for "reg­u­la­tor sens­ing lines," which it says are used to de­tect pres­sure in the dis­tri­bu­tion sys­tem so that reg­u­la­tors can con­trol sys­tem pres­sure.

Fed­eral in­ves­ti­ga­tors also noted that the util­ity's mon­i­tor­ing cen­ter in Colum­bus, Ohio, re­ceived two alerts reg­is­ter­ing high pres­sure in the Lawrence sys­tem just min­utes be­fore the ex­plo­sions.

The Ohio fa­cil­ity isn't able to close or open valves re­motely but quickly re­layed the high-pres­sure re­port to field tech­ni­cians in Mas­sachusetts, the re­port said.

Lo­cal util­ity of­fi­cials shut down the im­pacted reg­u­la­tor within about a half an hour, and closed the crit­i­cal gas dis­tri­bu­tion val­ues about three hours later, ac­cord­ing to the re­port.

The next stage of the fed­eral in­ves­ti­ga­tion will look at co­or­di­na­tion be­tween the emer­gency re­spon­ders and Columbia Gas and an anal­y­sis of the com­pany's en­gi­neer­ing, de­sign and con­struc­tion plans, ac­cord­ing to the re­port.

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