The Clean Water Act, passed in 1972, requires the EPA to regulate pollution discharges into U.S. waters. But the agency illegally exempted ballast water discharges from any regulation for 36 years.

“Pollutants and invasive species like the invasive overbite clam are threats that demand action, and it’s absurd that the EPA has abdicated its duty for so long and neglected to set firm limits on ...