A sewage spill that began on Jan. 19 in the Potomac River has become one of the largest, if not the largest, reported wastewater spills in U.S. history.

On Jan. 19, a section of the Potomac Interceptor sewer line collapsed in the Potomac River at a point off of Cabin John, Maryland, causing the release of hundreds of millions of gallons of raw sewage into the waterway. Regional environmental activists have called the spill undoubtedly one of the largest wastewater spills in the nation, with WTOP calling it the largest in U.S. history.