(April 20, 2018, 11:25 AM EDT) -- SEATTLE — The federal government agreed to pay $51 million to Boeing Co. to reimburse the company for the more than $220 million it has spent remediating contamination at a Superfund site in Washington, according to documents filed April 18 in a Washington federal court (Boeing Co. v. United States, No. 18-cv-567, W.D. Wash.)....