5,900 Natural Gas Leaks Discovered Under Washington, D.C.

http://www.sciencedaily.com/releases/2014/01/140116091143.htm

Jan. 16, 2014 — More than 5,893 leaks from aging natural gas pipelines have been found under the streets of Washington, D.C. by a research team from Duke University and Boston University.

A dozen of the leaks could have posed explosion risks, the researchers said. Some manholes had methane concentrations as high as 500,000 parts per million of natural gas -- about 10 times greater than the threshold at which explosions can occur.

Four months after phoning in the leaks to city authorities, the research team returned and found that nine were still emitting dangerous levels of methane. "Finding the leaks a second time, four months after we first reported them, was really surprising," said Robert B. Jackson, a professor of environmental sciences at Duke who led the study.

The researchers published their findings this week in the peer-reviewed journal Environmental Science & Technology.

-----

n addition to the explosion hazard, natural gas leaks also pose another threat: Methane, the primary ingredient of natural gas, is a powerful greenhouse gas that also can catalyze ozone formation. Pipeline leaks are the largest human-caused source of methane in the United States and contribute to $3 billion of lost and unaccounted for natural gas each year.

-----

Last year, the team mapped more than 3,300 natural-gas pipeline leaks beneath 785 road miles in the city of Boston. "The average density of leaks we mapped in the two cities is comparable, but the average methane concentrations are higher in Washington," said Nathan G. Phillips, a professor at Boston University's Department of Earth and Environment.

Like Washington and Boston, many U.S. cities have aging pipeline infrastructure that may be prone to leaks. The researchers recommend coordinated gas-leak mapping campaigns in cities where the infrastructure is deemed to be at risk.

-----

The new study comes at a time when the nation's aging pipeline infrastructure is generating increased legislative attention. Last November, Sen. Edward J. Markey (D-Mass.) introduced two new bills to speed up the replacement of natural gas pipelines in states with older infrastructures by offering new federal programs and incentives to help defray the costs associated with the repairs.

"We need to put the right financial incentives in place," said Jackson. "Companies and public utility commissions need help to fix leaks and replace old cast iron pipes more quickly."