More than 100 trees will be cut down, a wetland will be excavated and tons of dirt will be hauled away because hazardous materials were dumped last month on land owned by Prince William County, fire officials said.

Fourteen barrels, each containing 55 gallons of a substance believed to be paint thinner, were dumped June 18 near Dumfries and Spriggs roads, according to hazardous materials officer John Medici. The cleanup is expected to cost as much as $500,000, he said.

Darrell James Sturgell, 47, owner of D&K Auto Body of Dumfries, was arrested Wednesday in the incident and charged with felony illegal dumping, said Assistant Commonwealth's Attorney Wenda Travers.

A preliminary hearing has been scheduled for July 25. Sturgell, who was released on bond, could not be reached for comment.

Assistant County Attorney Angela Lemmon said her office will ask the Board of County Supervisors for permission to file a civil suit against Sturgell to recover the costs of the cleanup, which will include treating or removing all the dirt around the 10-by-20-foot dump site.

So far, the county has spent about $50,000 to package the barrels in larger containers and on laboratory tests to determine their contents, she said.

The barrels were discovered by Army Corps of Engineers surveyors working in the area. Two were full, two were empty and 10 had been hacked open with an ax, Medici said.

County officials said the dumping is the worst such incident in the county's history. A hazardous materials spill several years ago invovled thousands of gallons of fuel and cost about $500,000 to clean up, Medici said.

Officials were led to Sturgell's business by a black-and-white sticker bearing the D&K name attached to one of the barrels, he said.

At the time the barrels were found, illegal dumping of hazardous materials was punishable by imprisonment of up to one year and a fine of up to $10,000 for each day of violation.

The law changed July 1, allowing jail time of up to five years and a maximum fine of $25,000 per violation, Travers said. The new law also allows imprisonment for two to 15 years and a fine of up to $250,000 for anyone who dumps hazardous materials knowing that the incident might result in someone's death or serious injury, she said.

Lemmon said if the defendant is unable to pay for the cleanup and the county is unable to obtain federal funds, county taxpayers would pay the bill.

A special prosecutor from the Department of Justice is working on the case with local officials.

Tests are underway to show whether the barrels contain any extremely hazardous substances such as chlorine, ammonia and cyanide.

After the substance is definitely identified, officials will decide how to best remove it from the site.

The least expensive alternative would require that the trees in the area be cut down, their roots removed and treated to neutralize the hazardous material, and dirt from the site be dumped at the local landfill. The nearby wetland, which is home to several varieties of unusual plants, will have to be drained, dug up and possbily restored, Medici said.

All the work will be done by people trained in handling hazardous materials because of government regulations, he said.

The most expensive alternative would involve transporting the dirt to a dump licensed to accept hazardous materials, which would cost at least $100 a ton for dumping fees. The closest facility is in South Carolina, Medici said.