The Senate Appropriations Committee approved a measure yesterday that could force the Coast Guard to spend up to $500,000 of an emergency waste disposal fund to remove thousands of gallons of deadly chemicals from an old tank farm on the Nanticoke River near Sharptown, Md.

The presence of the chemicals near the small Eastern Shore community of 670 people has triggered a debate among federal, state and local officials over how soon the chemicals can be removed or who should remove them.

The Coast Guard, which had sent men to try to ensure there were no leaks from the tanks and which was helping federal and state agencies take samples from the 39 10,000-gallon structures, has for a month declined to declare the site an "imminent hazard."

However, according to the language approved by the Approriations Committee yesterday on the motion of Sen. Birch Bayh (D-Ind.), the site is "an imminent public safety hazard."

The amendment added that "the committee expects the Coast Guard to remove these materials to a safe storage facility where they present no hazard to the environment."

Bayh had introduced the amendment on behalf of Sen. Charles McC. Mathias (R-Md.), who could not attend the committee session, according to Mathias' press aide Jack Eddinger.

The entire transportation appropriation bill, which includes $10 million for the Coast Guard's emergency clean-up fund, now goes to a House-Senate conference committee, and then must be approved by the membership of both the House and Senate.

"That sheds a little different light on the subject," said Sharptown Mayor Ralph Cordey, when told of the decision yesterday. Cordrey has been pushing hard to get someone to remove the chemicals -- a disposal operation that Coast Guard officials estimate will cost at least $200,000, or four times the town's annual budget.

"I'm happy," he added. "I can't be anything else."

Coast Guard Capt. J. William Kime, who has been supervising the operations at the Sharptown site for the last month said yesterday that as far as he is concerned the major stumbling block to removal of the chemicals is still the problem of finding an acceptable disposal site.

According to Kime, final sampling test of the tanks' contents indicate that they contain 24,500 gallons of waste oil laced with 500 parts per million of the potent cancer-causing agent PCB. Another 35,000 gallons of oil at the site contain oil mixed with the solvents benzene and xylene.

Xylene is highly flammable, while benzene is also a cancer-causing chemical.

The tank farm was built as part of an oil reprocessing plant in 1971. The plant did little business and was closed by the state Department of Natural Resources two years ago.