A Houston-based trash-hauling company that imports tons of trash into Virginia filed suit today challenging a new set of laws designed to limit the flow of garbage into the state.

In a federal court filing here, Waste Management Inc. said laws enacted this year by the General Assembly were unconstitutionally interfering with its right to import garbage. The new laws bar trash barges from Virginia rivers, put a lid on landfill growth and impose other restrictions.

"The transport of articles of commerce across state lines is a basic freedom guaranteed by the founding fathers," said John Skoutelas, a regional vice president and general counsel of Waste Management.

"These laws are not only unconstitutional, they also constitute a giant step backward for the commonwealth's environment," Skoutelas said. "The barge restrictions prevent the use of a safe and environmentally sound alternative to tractor-trailer traffic on our highways."

David B. Botkins, a spokesman for state Attorney General Mark L. Earley (R), said the office will act decisively to uphold the four laws, which are scheduled to take effect in three weeks.

"The commonwealth is confident of the constitutionality of the statutes and will defend them vigorously," Botkins said.

In a statement, Gov. James S. Gilmore III (R) noted that Waste Management recently was fined for dumping medical waste in a landfill outside Richmond, and he criticized the company's suit as a challenge against "Virginia's right to protect her waterways and landscape from the onslaught of trash."