Nearly 6,000 Gas Leaks Discovered under Washington D.C.

The underground seepage of natural gas from aging pipes in Washington D.C. is creating the potential for explosions in some locations of the nation's capital, according to a new study by Robert Jackson, who joined the Stanford faculty on January 1.

“Repairing these leaks will improve air quality, increase consumer health and safety, and save money,” said Jackson, the newly-appointed Kevin and Michelle Douglas Professor of Environment and Energy in the Stanford School of Earth Sciences. “Pipeline safety has been improving over the last two decades. Now is the time to make it even better.” Nationally, natural gas pipeline failures cause an average of 17 fatalities, 68 injuries, and $133 million in property damage annually, according to the U.S. Pipeline and Hazardous Materials Safety Administration. Jackson conducted the research, detailed in the American Chemical Society journal Environmental Science & Technology, while he was on the faculty at Duke University.

In the study, Jackson and his colleagues mapped the underground gas pipelines in Washington D.C. To do this, they drove all of the 1,500 miles of streets in the capital in a car that was equipped with GPS and an instrument that took methane readings close to the ground every second. They found nearly 6,000 leaks, with the highest concentration of methane at about 45 times what would be expected with no leak. The team speculates that the leaks are coming from the city's aging cast-iron pipe infrastructure, which makes up about 35 percent of the capital's main pipes.

At 19 sites with high leakage, the researchers tested the manholes. They found that some manholes had methane concentrations as high as 500,000 parts per million — about 10 times greater than the threshold at which explosions can occur. The team notified the gas company, and a follow-up test in June 2013 found that nine manholes still had dangerously high levels of methane. “Finding the leaks a second time, four months after we first reported them, was really surprising,” Jackson said.

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,” Jackson said. “Companies and public utility commissions need help to fix leaks and replace old cast iron pipes more quickly.”

In 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.

Jackson is also a senior fellow in the Stanford Woods Institute for the Environment and the Precourt Institute for Energy.