The pace of construction is picking up at Singleton's Grove in Centreville, where a gusher from a broken gasoline pipeline drove residents from their homes and interrupted groundbreaking on new units June 11.

Although the builder, US Homes, is still prohibited from blasting in some areas, construction has been authorized on all but 25 of the roughly 600 potential homes, according to officials.

Meanwhile, the county has filed misdemeanor charges against the company whose bulldozer allegedly caused the pipeline rupture. F.E. Gregory and Sons Inc. of Gaithersburg is charged with failing to notify Miss Utility -- the service that makes sure construction does not interfere with buried utility lines -- before digging at the site and failing to take appropriate precautions near an existing utility line.

F.E. Gregory officials could not be reached for comment.

Conviction on each charge carries up to 30 days' imprisonment and a $1,000 fine. The case is scheduled to be heard in Fairfax General District Court Nov. 5.

At the time of the accident, bulldozer operator Keith Wayne Carpenter said he punctured the 32-inch-diameter pipe as he and his fellow workers cleared the way for a sidewalk. The rupture released a 100-foot-high geyser of super-unleaded gasoline for about 10 minutes.

Irving Birmingham, director of Fairfax County's Division of Design Review and coordinator of clean-up efforts at the site, said exhaustive efforts, including a seismic survey, have failed to locate much of the thousands of gallons of gasoline that seeped into the soil at Singleton's Grove.

"We've sunk over 14 wells, and all but two of the wells came up dry," Birmingham said. "We've taken the wells all the way down to the water table, and it's just not there."

In order to purge the area of the fuel, Birmingham said, the county will put pipes underground and blow hot air through the soil until the vapors that result show no residue. The procedure is expected to begin in the next two weeks.