http://www.washingtontimes.com/news/2012/may/24/settlement-reached-in-chantilly-gas-leak-explosion/
Looks like it was faulty infrastructure. Brookfield residents can expect some inspections/gas line work over the next few months.
"Washington Gas has to pay Virginia $154,800 under a settlement order from the State Corporation Commission stemming from an investigation into a December 2010 explosion that destroyed a home in Chantilly.
While not admitting or denying liability, the company is on the hook for another $219,700 if it doesn’t replace all the copper service lines in the Brookfield community by the end of November, among other requirements.
The company was charged with nine violations of the SCC’s gas pipeline safety standards in the order. Those include not recording test readings of natural gas after the incident occurred, failing to document leakage test readings and the locations of gas discovered as part of the investigation, failing to perform a complete leak survey of the service line to the address, and failing to identify and record a “service violation” of the line under the home’s foundation during a June 1, 2009, leak survey"