Since 2004, ships from overseas have been required to dump and replace ballast water, or rinse empty tanks, at least 200 miles from U.S. waters. But studies show that up to 30 percent of organisms remain alive in the tanks, said Andrew Cohen, director of the Center for Research on Aquatic Bioinvasions in Richmond, Calif.
"It's a pretty weak approach," Cohen said.
Researchers have spent years developing methods of sanitizing ballast with ultraviolet light, chemicals, filters and even oxygen depletion.
A first draft of the Coast Guard regulations would adopt international limits on numbers of organisms per cubic meter of ballast water.
The ceilings would take effect next year for new vessels and be phased in over several years for existing ones. A second set of limits about 1,000 times stronger in establishing limits per cubic meter of ballast water would be imposed later if studies show that could be accomplished.
Environmentalists are pushing for a quicker timetable, while shippers want it lengthened.
Cmdr. Gary Croot, chief of the Coast Guard's Environmental Standards Division, said the final rules being released this spring will reflect public feedback. "We certainly don't want to establish a standard that no one can comply with," he said.
New York's standard, which takes effect in 2012, would be 100 times more stringent than the proposed Coast Guard limit on organisms. California has adopted even tougher standards, but regulators say enforcement may be delayed.
"There have been ship owners ready and willing to make investments in ballast water treatment technology who have held back because they don't want to spend a million dollars on some system that may have to be ripped out in five years because it doesn't meet the standards," said Jennifer Carpenter, senior vice present of American Waterways Operators, an industry trade group.
EPA and the Coast Guard have commissioned studies to determine which standards and technology would work best. The number of live organisms permitted under the Coast Guard's draft policy is the equivalent of one drop of water in 20 Olympic-sized swimming pools, Croot said. Going significantly beyond that would be harder and costlier.
"If you want to make a car perfectly safe, conceivably that could be done, but at what expense?" Croot said.
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