Bilge pollution is a type of water pollution that occurs when the bilge water in a ship's hull is discharged into the ocean.^[1][2][3] In a research published in 2019, it was estimated that up to 3000 cases of bilge dumping happen in Europe every year.^[1] According to another estimate, approximately 52.8 million gallons of pollutants are discharged into the ocean annually.^[4]

Treatment of bilge water, in which all contaminants are removed, is the preferred method of dealing with bilge water pollution.^[1] Due to increased operational costs, companies mostly dump waste directly into the ocean without properly processing it.^[1] Due to the presence of carcinogenic chemicals, bilge water waste is considered a threat to marine life and human health.^[5]

Bilge pollution can be prevented if bilge water, which is a normal accumulation of polluted water in a marine vessel, is treated before it is discharged from said vessel.

Bilge water treatment in the United States is largely regulated by the Clean Water Act (CWA), which is jointly enforced by the United States Environmental Protection Agency (EPA) and the United States Coast Guard.^[6] Section 301(a) of the CWA outlaws the discharge of any pollutant from a marine vessel, unless the discharge is in compliance with regulations provided in other sections of the CWA.^[6] Bilge pollution is defined as a type of ‘‘discharge incidental to the normal operation of a vessel" in § 1322 of the CWA.^[7] The EPA sets standards for the amount of different pollutants that bilge water can contain before being discharged into large bodies of water. If the bilge water is not in compliance with these standards at the time of the bilge water being released, then individuals and/or companies involved in the pollution may face fines.^[8]