President Donald Trump on Tuesday signed legislation authorizing a new Coast Guard bill from Congress that includes the first-ever comprehensive plan to regulate ballast water as a pollutant.

The bill calls for ballast water discharge to be regulated under Clean Water Act, under authority of the Environmental Protection Agency with enforcement by the Coast Guard.

The bill prohibits states from enacting their own regulations for ballast, but does leave an opening for the Great Lakes as a region to adopt stricter or additional standards.

Ballast water is blamed for the spread of many invasive species that hitchhike from overseas ports to U.S. ports, including across the Great Lakes - things like zebra mussels, goby, ruffe and spiny water fleas.

The legislation also includes $50 million a year for a new program under the EPA for monitoring and responding to outbreaks of invasive species in the Great Lakes and to help develop ballast-control technologies for lakers, freighters that never leave the Great Lakes. The bill also calls for new research into the impact of oil spills in freshwater such as the great lakes.

The ballast measures were first ordered by a federal court a decade ago but have been held up in Congress as ship owners and environmental groups battled over the cost of action and inaction.