CSX Transportation has agreed to pay the District of Columbia $7.5 million toward environmental cleanup programs as part of a settlement reached this month after D.C. inspectors witnessed pollutants leeching from the company's Benning Road rail yard, the Washington Post reports.

The railroad company also must pay a $500,000 civil penalty, reimburse the District Department of the Environment for oversight costs and clean up the pollutants coming from its rail yard in Northeast.

"This settlement is intended to send a strong message -- that the District will aggressively, but thoughtfully, pursue entities that harm the environment and threaten public health," Attorney General Peter Nickles said in a statement.

Inspectors from the Environment Department saw petroleum discharges in the Smith Branch, also known as the Fort Dupont stream, which is a tributary to the Anacostia River. Stopping the petroleum and other pollutants leeching into the water by the rail yard is part of a larger effort by the city to clean up the Anacostia, said Christophe A.G. Tulou, acting director of the Environment Department.

In addition to the remediation of Popular Point and the Navy Yard, the District is now responsible for removing trash from the river and its tributaries, because of federally approved pollution limits. Maryland and the District must come up with a plan to remove 600 tons of trash from the Anacostia per year.

CSXT has begun remediating the site and will install an improved storm water management system as part of the cleanup, according to District officials.

"We will continue to work closely with the District under our agreement to monitor and mitigate any adverse environmental impacts associated with the former locomotive fueling system at Benning Yard," Skip Elliott, CSXT's vice president of public safety and the environment, said in a statement.