Two family-owned Maryland trash companies pleaded guilty yesterday to federal and state criminal charges, admitting they defrauded the Navy of $800,000 by illegally shipping garbage to Virginia that they were supposed to dump in Maryland or deposit at a District trash transfer station.

Prosecutors said that the fees for dumping the trash in Virginia were about one-fourth the costs in Maryland and that the firms defrauded the Navy by pocketing the difference.

Under the scheme described in U.S. District Court in Greenbelt and later in Prince George's County and St. Mary's County circuit courts, the firms set up fake recycling centers in the two counties that actually were trash transfer stations in violation of state anti-littering laws.

The firms and four of their officers agreed to pay nearly $3.5 million in fines as part of their plea agreements with federal and state prosecutors. They also agreed to make a public apology by taking out full-page newspaper advertisements.

"The state is very serious about addressing the problems of solid waste pollution," said John R. Lilly, a Maryland assistant attorney general, at the hearing in St. Mary's County.

St. Mary's County State's Attorney Richard Fritz said: "This case should go out as an eye-opener for all commercial waste haulers in the county."

A.W. Stevens and Sons Waste Disposal Systems Inc. of Upper Marlboro and St. Mary's Disposal Systems Inc. of St. Mary's County pleaded guilty to 17 federal charges, including conspiracy, filing false claims and violating the Clean Water Act. They pleaded guilty in the two county courthouses to violating the state anti-littering laws.

The two companies were owned and operated by Albert W. Stevens, 67, of Annapolis, and three other family members: Susan Goolsby Stevens, 46; Michael W. Stevens, 45; and Patrick T. Stevens, 43.

The firms have been sold. Albert Stevens and an attorney representing the two companies declined to comment yesterday.

The companies and their former owners agreed to pay a federal criminal fine of $1.3 million as well as a federal civil penalty of $2 million. They also agreed to pay fines of $80,000 each to Prince George's County and St. Mary's County.

The two waste-disposal companies and Michael W. Stevens, who pleaded guilty to a federal charge of filing false claims against the Navy, are scheduled to be sentenced in U.S. District Court in Greenbelt on Sept. 21.

According to a statement of facts presented in federal court, the two firms held federal contracts from 1992 to 1997 to dispose of garbage from the U.S. Naval Academy in Annapolis, the Patuxent River Naval Air Station in St. Mary's and the Indian Head Naval Ordnance Station in Prince George's.

Rather than dump the garbage in landfills in Maryland or take it to the District transfer station, as stipulated by the contracts, the companies smuggled the trash to Virginia and falsified receipts that they submitted to the Navy, court records state.

The plea bargain was the result of a 2 1/2-year investigation by federal, state and local officials as part of the Prince George's County Environmental Crimes Task Force.

The probe was sparked by a tip from the Prince George's County Department of Public Health after residents complained about smells coming from property owned by A.W. Stevens and Sons at 7910 Penn Randall Pl., investigators said.

Prosecutors said the firm had disguised the site as a recycling center, when in fact it was being used illegally as a solid waste transfer station. Garbage collection trucks filled with Navy trash would dump their cargo on the ground so it could be picked up by tractor-trailers and taken to landfills in Waverly and Charles City, Va., according to the statement.

In addition, the illegal Prince George's County transfer site leached pollutants from the company's truck-washing operations into a tributary of the Potomac River, according to court records.

St. Mary's Disposal Systems Inc. ran a similar covert garbage transfer station on Route 4 in St. Mary's, which it used to smuggle trash collected from the Patuxent River Naval Air Station, according to court records.

Neither transfer station was permitted or licensed by local or state authorities.

Staff writer Jessie Mangaliman contributed to this report.