The amendment, offered by Representative Don Young, Republican of Alaska, would prohibit new offshore wind facilities within 1.5 nautical miles of a shipping lane or a ferry route. That would rule out construction of the installation, proposed for Nantucket Sound. The budget bill awaits action in a House-Senate conference committee.

The installation would consist of 130 turbines in a grid that would occupy 24 square miles in the sound. Each tower, with its turbine and blades, would rise 420 feet above the water. The developer, a private company called Cape Wind Associates, says the turbines could produce three-quarters of the electricity now used on Cape Cod, Martha's Vineyard and Nantucket.

Greenpeace, the American Lung Association and other organizations endorse the plan as an important step in reducing pollution and global warming.

But fishery groups, many local communities and Massachusetts political figures like Gov. Mitt Romney and Senator Edward M. Kennedy say that Nantucket Sound, a major attraction for the region's tourism economy, is an inappropriate place for so large an industrial installation and that nothing should be built in federal coastal waters until the government has devised a way to regulate development there.

Christine Real de Azua of the American Wind Energy Association, a trade group, said Mr. Young's amendment was not the way to address those objections.

"It's 'behind the closed doors' kind of government which is really not in the public interest," she said.

If Mr. Young "were really worried about safety issues," she said, "he would be worried about oil rigs which are allowed within 500 feet of a shipping channel."

Ms. Real de Azua and Mark Rodgers, a spokesman for Cape Wind, said that in Denmark, the country with the most experience with offshore wind farms, there were installations only about a quarter-mile from major shipping channels into Copenhagen Harbor and about a mile from a major channel in the Baltic Sea. Those shipping lanes handle far more traffic than Nantucket Sound, they said.

They said concern had arisen in Britain over whether wind turbines might interfere with ships' radar. But even there, they said, the issue involves distances of 500 yards or so from the turbines, far less than the 1.5-mile buffer sought by the Young amendment.