The U.S. government has agreed to chip in $51 million to clean up pollution at a Seattle site where Boeing made and tested B-17, B-52 and other bomber planes beginning in World War II.

Boeing had sought to have the government pay for a share of the company’s cleanup costs, which it says have reached $220 million and counting. The Departments of Defense, Commerce and other agencies agreed in a proposed settlement filed Wednesday in U.S. District Court in Seattle.