Washington Gas has found about 1,400 active leaks in underground service lines within a 100-square-mile area of Prince George's County, according to a report the utility sent late yesterday to the Maryland Public Service Commission.
The leaks are not considered hazardous because the vapor remains underground and has not migrated into homes or buildings, Washington Gas spokesman Tim Sargeant said after releasing the 33-page report. The company plans to repair all leaks within six months, the report said.
Washington Gas has been under scrutiny since a District Heights house exploded in March after its residents complained of a gas odor. Since then, company officials have acknowledged that they had noticed an increase in the number of leaks in the county a year and a half ago.
Sargeant could not say how many leaks the company has found since first discovering the problem. He also could not say how many leaks have been considered hazardous. Such leaks have been fixed immediately, he said. "We've been addressing this since before the District Heights explosion," he said. "We have continued to work on fixing the leaks."
Company officials have attributed the leaks to deterioration of rubber seals within mechanical couplings that link service lines, but they have not found a cause. The couplings were installed throughout the region until the 1970s, but Prince George's has a large concentration of them. The utility said it is investigating why the county has so many of the couplings.
The commission, which regulates utilities in the state, opened an inquiry into the gas leaks 15 days ago and set yesterday as the deadline for Washington Gas to submit answers to seven questions, including the location of leaks and a description of the investigation into their cause. The commission also asked the utility to provide monthly reports on the status of the repairs.
Christine Nizer, a spokeswoman for the commission, said last night that agency officials had not had a chance to read the report.
"We did receive the documents that we requested from Washington Gas," she said. "The commissioners will review those documents and take appropriate actions after having a chance to review them."
The report included the locations of the leaks, which company officials said are primarily south of Route 50. Some of the neighborhoods in the affected area are in Lanham, Clinton, Suitland, Oxon Hill and Capitol Heights.
Washington Gas officials said they have hired several firms, including Akron Rubber Development Laboratory Inc., to determine the cause of the leaks. Sargeant said the firms have not yet produced any findings.
In the meantime, the company plans to spend $75 million to repair the faulty lines.
The project will involve inserting new plastic pipes that do not require couplings into the existing steel service lines that lead into homes. If that doesn't work, the company will replace the service lines. Couplings on the gas mains outside homes and beneath streets will be sealed with a permanent bonding material. If that doesn't work, those, too, will be replaced.
In an effort to get the work done on time, the company will hire 60 outside contractor crews to supplement its employees.