Image by flickr user JenniferWoodardMaderazoImage by 20080521cargo_ship_pollution.jpg Cargo ships generally burn a cheap, tar-like diesel which has a sulfur content many thousands of of times higher than the diesel used by cargo trucks.

Highly toxic air emissions from cargo ships (which are prevalent at Charleston's ports) would be slashed under legislation that passed a U.S. Senate committee.

The bill was introduced by a Californian Democrat, and faced many objections from Republicans.

The massive ships burn a cheap, tar-like diesel which has a sulfur content many thousands of of times higher than the diesel used by cargo trucks. The emissions can aggravate asthma or cause other respiratory illness.

Wikipedia reports:
Exhaust emissions from ships are considered to be a significant source of air pollution. "Seagoing vessels are responsible for an estimated 14 percent of emissions of nitrogen from fossil fuels and 16 percent of the emissions of sulfur from petroleum uses into the atmosphere." In Europe ships make up a large percentage of the sulfur introduced to the air, "...as much sulfur as all the cars, lorries and factories in Europe put together." "By 2010, up to 40% of air pollution over land could come from ships."

Shipping is a major source of Charleston's air pollution. There are also rising fears that the upcoming port expansion will only worsen things.

Last year, California required that ships burn cleaner fuel within 24 miles of shore.