"TRAVERSE CITY, Mich. — The Environmental Protection Agency proposed stricter requirements Wednesday for cleaning ballast water that keeps ships upright in rolling seas but enables invasive species to reach U.S. waters, where they have ravaged ecosystems and caused billions of dollars in economic losses."

"The new standards would require commercial vessels to install technology strong enough to kill at least some of the fish, mussels and even microorganisms such as viruses that lurk in ballast water before it’s dumped into harbors after ships arrive in port. Environmentalists whose lawsuits forced the EPA to implement rules in the first place said the new proposal is largely inadequate.

More than 180 exotic species have invaded the Great Lakes, about two-thirds of which are believed to have been carried in ballast water. Among them are zebra and quagga mussels, which have spread across most of the lakes and turned up as far away as California. Ballast water also has brought invaders to ocean coasts, including Asian clams in San Francisco Bay and Japanese shore crabs on the Atlantic seaboard."

John Flesher reports for the Associated Press November 30, 2011. [2]