The Maryland House of Delegates approved a proposed mandatory seat belt law on a voice vote Saturday, but it did not give the proposal final approval. The House voted 77 to 51 on an amendment weakening the measure.

The Maryland House of Delegates gave tentative approval today to a bill that would void new pesticide laws in Prince George's and Montgomery counties by prohibiting local jurisdictions from enacting laws regulating the use of lawn chemicals.

The House action stymied an effort by Prince George's delegates to amend the bill to allow existing local laws to stand. The amendment, sponsored by Prince George's Del. William Bevan, died on a 65-to-38 vote.

"We need a uniform law statewide," said sponsor Del. George Littrell (D-Frederick), charging that Bevan's amendment threatened to gut the bill. Local efforts to enforce stricter requirements than those imposed by the state would conflict with federal law, he said.

"It is not in the best interest of the state to allow local regulations," Littrell said.

A separate measure, sponsored by Del. Joan Pitkin (D-Prince George's) and awaiting House action, would require public notification when pesticides are applied on lawns by professional applicators. The ordinances in Prince George's and Montgomery require advance notice.

Pitkin said the House rejection of Bevan's effort did not mean that her proposal would fail as well.

"It's merely giving localities an interpretive authority," she said. "If the counties want to adopt more stringent restrictions, it's okay."

"Our constituents are entitled to the protections that our local laws allow," said Del. Ida Ruben (D-Montgomery).

But Littrell and his supporters argued that the agriculture committees in Congress have said setting regulations for pesticide use is a state responsibility. The Maryland attorney general's office has issued an opinion, requested by Del. Jerry Hyatt (D-Montgomery) that makes a similar point.

In that opinion, the attorney general's office said that the provisions of the local laws are preempted by federal regulations.

Both the Montgomery and Prince George's county councils adopted the pesticide notification regulations during the past six months. State law does not require advance notice when lawns are sprayed.

Del. Gary Alexander (D-Prince George's) and Bevan argued that nothing in the federal law prohibits states from granting localities the power to enact their own legislation. "This bill is trying to put a nail in the coffin and . . . prohibit the local option," Bevan said. "The argument about federal involvement is not relevant."

Both county councils passed the ordinances, which were aimed at lawn care companies, after public hearings in which people who suffer from chemical sensitivity said that advance warning of pesticide application could prevent illness.

A similar measure, sponsored by state Sen. Stewart Bainum (D-Montgomery), has won final Senate approval and is awaiting House action.