Nov. 21, 1996 Thirty-three people were killed and dozens hurt when a gas explosion ripped through a shoe store and office building in Rio Piedras, Puerto Rico.

Dec. 11, 1998 A work crew punctured an underground natural gas pipeline in St. Cloud, Minn. The resulting blast killed four people, injured 11, and destroyed six buildings.

Aug. 19, 2000 A pipeline explosion near Carlsbad, N.M., killed 12 people.

Dec. 13, 2005 Workers removing an underground oil tank in Bergenfield, N.J., undermined a gas pipeline. The gas line later failed, causing an explosion. Three people were killed.

Nov. 11, 2006 A bulldozer operator was incinerated when his machine struck the Rockies Express (REX) interstate gas pipeline in Cheyenne, Wyo.

Sept. 14, 2008 A natural gas pipeline exploded in Appomattox, Va., injuring five people, destroying two homes, and damaging 100 other properties. Federal officials later fined the Williams company nearly $1 million. The Transcontinental interstate transmission line failed though it had passed safety tests only three months before.

Nov. 14, 2008 Three homes were destroyed and a woman badly burned when a gas gathering line exploded in Grady County, Okla.

Nov. 14, 2009 The REX pipeline failed near Philo, Ohio. Several homes were evacuated. No one was hurt.

June 8, 2010 Two workers died when a bulldozer struck a gas gathering line in Darrouzett in the Texas panhandle.

June 29, 2010 Three men working on a gas gathering line, also in Grady County, Okla., were hurt when it exploded.

Sept. 9, 2010 A high-pressure gas pipeline exploded in San Bruno, a suburb of San Francisco. The blast destroyed 38 homes and damaged 120 homes. Eight people died and many were injured.

Jan. 11, 2011 A leak was found in the Millennium interstate transmission line, built in 2009, in New York state. Later investigation found that a section had flunked a visual inspection and was set aside but was installed by mistake. No one was hurt.

Jan. 18, 2011 A gas main being repaired in Philadelphia exploded, killing a PGW repair crew member and injuring six people.

Feb. 10, 2011 Five people were killed and eight homes were destroyed in a gas explosion and fire in Allentown. After a 1990 gas explosion in Allentown, federal safety investigators had warned that iron gas mains needed replacement in the town.

Nov. 16, 2011 Two people were hurt and three homes destroyed when an interstate natural gas transmission line exploded south of Zanesville, Ohio. The accident, apparently caused by a defective weld, was the third failure on El Paso Corp.’s Tennessee Gas Pipeline in 2011.

Dec. 3, 2011 A natural gas interstate transmission line ruptured near Sweetwater, Ala., with an explosion that could be heard for 30 miles. No one was hurt in the failure, which took place on the Williams company’s Transcontinental line.