The damaged rubber seals on aging metal pipe couplings that caused nearly 1,400 leaks in underground gas lines in Prince George's County have been fixed, according to Washington Gas officials.

James H. DeGraffenreidt Jr., chief executive of the utility that serves almost a million customers in the Washington region, told members of the Prince George's County Council on Tuesday night that the repairs were completed in late August, two months ahead of schedule.

But the $144 million project that began in April is still underway. DeGraffenreidt said workers are continuing to identify additional leaks, schedule repairs and replace the thousands of gas mains and service lines that have metal couplings. Tim Sargeant, a spokesman for Washington Gas, said that work will not be completed until late 2007.

Council member David Harrington (D-Cheverly) said Washington Gas, after some fits and starts, appears to be "moving in the right direction."

But not everyone is satisfied with the pace of the progress.

District Heights Mayor Carol D. Johnson said she contacted Washington Gas last month after finding holes, several feet deep, throughout her town.

"Holes weren't covered; they were left open, and children were playing in them," Johnson said. "There was no notification to residents when they were working on streets. No hotline. Nothing."

David Kenahan, project manager for Washington Gas, said any damage made to pavement during the repairs has been temporarily repaired. Permanent paving is not done until projects are complete, he said. But workers are trying to monitor and maintain the temporary patches. They are also trying to notify residents and local officials when work arises in an area.

Things have improved recently, Johnson said.

"Now I'm trying to give them the opportunity to make good on what they said they were going to do," she said.

Washington Gas launched a study of its service in Prince George's after a District Heights house exploded in late March. Residents had complained of gas odors before the blast.

In July, the utility concluded that molecular differences in the imported liquefied natural gas it began using in 2003 were drying the seals on the couplings that link sections of pipe. Sargeant said the company has found a chemical additive that alters gas composition and reverses the damage to the seals. He said the utility is conducting additional studies.

The March explosion led to an investigation earlier this year by the Maryland Public Service Commission.