Senators from Virginia and other states where interstate trash shipments have raised alarm urged Congress yesterday to set national limits on the garbage trade, but they found their path littered with obstacles.

The advocates of new regulation want Congress to fill a legal void created in 1994 when the U.S. Supreme Court ruled that state regulations on trash imports were unconstitutional intrusions on interstate commerce. Sponsors of three bills include Virginia's two senators and others from Indiana, Ohio and Pennsylvania.

Pennsylvania and Virginia rank first and second nationally as importers of trash, a lucrative business for the companies that haul other communities' garbage and for the jurisdictions willing to receive it.

"The shipment of interstate garbage is different from other commodities," said Sen. Evan Bayh (D-Ind.), who is sponsoring legislation with Sen. George V. Voinovich (R-Ohio) that would permit states to freeze trash imports at 1993 levels.

"It's different when residents in a community find used needle containers . . . infectious medical waste . . . [and] large trucks used to transport the garbage all too often containing maggots and vermin," Bayh said. "Fear goes up."

A bill sponsored by Sen. Arlen Specter (R-Pa.) would track garbage shipments and permit localities to ratchet down waste imports by type. A third bill, sponsored by Virginia Sens. Charles S. Robb (D) and John W. Warner (R) would permit states to freeze imports at 1998 levels.

Among the obstacles the proponents face is Sen. John H. Chafee (R-R.I.), who chairs the Committee on Environment and Public Works, sponsor of yesterday's hearing on Capitol Hill.

Chafee said that after a decade of futile congressional efforts to regulate the industry, more stringent environmental standards have improved conditions at many landfills. At the same time, he said, concerns have abated that the 1994 court decision would undermine the financing of improved local waste facilities, raising the bar for new legislation.

"Things have changed," Chafee said. "The proponents of federal legislation of interstate waste and flow control in 1999 have a special burden to make the case that legislation is indeed still needed."

In the House, Commerce Committee Chairman Thomas J. Bliley Jr. (R-Va.), who has opposed trash limits, has declined to schedule hearings on a companion version of the Specter bill until a consensus among the states is reached.

Yesterday, Warner questioned whether some of Virginia's leaders had done enough.

"I don't have an answer why our state hasn't enacted such legislation that is necessary to bring about a correction of the existing situation," Warner said. "I can't explain why the Virginia congressional delegation . . . has taken views somewhat different from mine, but I'm going to forge ahead by myself, with Senator Robb."

Virginia Gov. James S. Gilmore III (R) pushed through state legislation earlier this year to cap waste imports at 1998 levels and ban trash barges from state waterways, but the industry last week filed a legal challenge in federal court.

Meanwhile, the state environmental agency reported that out-of-state garbage shipped to Virginia rose to 4.6 million tons in 1998 from 3.2 million tons in 1997.