Michigan — and the entire region — should benefit from new EPA requirements for purifying ballast water dumped from ships on the Great Lakes.
Most large vessels use ballast tanks filled with water as a balancing mechanism. Researchers think these tanks also provide convenient hiding places for exotic species hitching a ride from foreign waters.
A 2002 state law required all oceangoing vessels to self-police their practices for dumping ballast water. In 2008, the law was toughened, requiring all ships incoming from the Atlantic and docking in Michigan to show a permit proving treatments were used on discharged water or face fines.
The law was tough, but it didn’t solve what was essentially a regional problem — no other states followed Michigan’s lead, so many Great Lakes ports were unprotected. Things have finally changed. Under new rules released last week by the EPA, vessels longer than 79 feet — perhaps 60,000 ships in total — must treat ballast water with technology such as ultraviolet light or chemicals to kill organisms before discharge.
The new guidelines don’t apply to vessels sailing only within the Great Lakes, a provision criticized by environmentalists because it may allow ships to transport invasives quickly around the lakes. But the move should close the window of opportunity for potential future invaders.
The EPA rules impose international cleanliness standards that the Coast Guard adopted last year, bringing some harmony to a formerly dissonant regulatory environment. The entire Great Lakes basin will be covered by one set of rules.
Studies by the EPA’s science advisory board and the National Research Council backed the new standards, which limit the number of living organisms allowed in a given volume of ballast water.
Under the new rules, ships built after Dec. 1 will have to immediately comply with the treatment standards. The requirements will be phased in for existing vessels, with treatment technology gradually installed as ships undergo maintenance.