A ruling by a federal judge last week against an Indiana law regulating hazardous waste shipments could conflict with Idaho Gov. Cecil Andrus' attempts to halt such shipments into his state.

A U.S. District judge in Indianapolis ruled a new state law regulating solid and hazardous waste shipments into Indiana violated the U.S. Constitution's commerce clause. It was the latest in a series of federal rulings against states' attempts to block the trash from crossing their borders.The commerce clause states Congress is authorized "to regulate commerce with foreign nations, and among the several states."

Though it has not closed its borders, Idaho is reluctant to accept waste from some states.

Andrus has said Idaho is willing to receive waste from states that have some kind of hazardous waste disposal or are working in good faith on developing them, said Marc Johnson, Andrus' chief of state.

But states with no such facilities, and not trying to pull their own weight, need not look at Idaho as a dumping ground for their waste, Johnson said.

In 1990, Idaho received 67,475 tons of waste deemed hazardous by state or federal regulations for disposal at the Envirosafe toxic waste dump near Grand View.

South Carolina, Indiana and other states are "clearly losing" in trying to convince judges they can bar out-of-state waste haulers from their disposal sites, said John Thomasian, an environmental researcher for the National Governors Association.

The commerce clause does not prevent Congress from passing legislation delegating that regulatory authority to the states for specified reasons, he added.

Thomasian said his group will lobby to persuade Congress to grant such an exemption from the clause to states that want to limit out-of-state trash.

The courts have shown they believe unilateral bans violate the Constitution's protection of interstate commerce, said Allen Blakey, spokesman for the National Solid Wastes Management Association.