WASHINGTON (AP) — Dangerous air emissions from giant cargo ships would be sharply reduced under legislation endorsed by a Senate committee Wednesday over the objections of Republicans.

The bill by Democratic Sen. Barbara Boxer, chairwoman of the Senate Environment and Public Works Committee, would require much cleaner fuel to be used by US or foreign vessels that use US ports.

The cheap, asphalt-like diesel that oceangoing ships burn has a sulphur content many thousand times higher than the diesel sold for US trucks, which could lead to unsafe sulphur oxide emissions that can aggravate asthma and cause other respiratory illnesses.

"The folks who live around ports and who work at the ports deserve to have the cleanest air possible. That fuel is available," Boxer said before the committee passed the bill on voice vote. The vote sent the legislation to the Senate for action.

The South Coast Air Quality Management District, a Southern California air-regulatory board, has said that marine vessels are the largest uncontrolled sources of air pollution in many areas of the country and responsible for at least 2,000 to 5,000 premature deaths each year.

Republicans contended that the most polluted ports can be found in Boxer's home state, California, particularly the giant ports of Los Angeles and Long Beach. "The problem is not universal. The problem is in California right now," said Republican Sen. James Inhofe, the top committee Republican. "Perhaps if I were a senator from California, I would be supporting this, too, but I'm not." He represents landlocked Oklahoma.