Commonwealth of Massachusetts prosecutors have agreed to drop a manslaughter charge against Powers Fasteners Inc. — the only company to face state criminal charges in connection with the fatal collapse of a section of Big Dig tunnel — after the New York epoxy vendor agreed to pay $16 million to the state and city. Powers supplied the bolts and the epoxy, a super glue, that contractors used to secure heavy concrete panels in the Interstate 90 Connector tunnel. The ceiling hung off rods attached to the bolts about 4 feet below the tunnel roof to create a crawl space used for ventilation. Over time, the epoxy weakened and slowly slipped out of the tunnel roof. Contractors observed the creep of the bolts long before the tunnel was opened to traffic in 2003, and Powers representatives met with project officials on the site of an eventual accident to investigate the creep, but they never resolved the issue. Under the terms of the settlement, the company agreed to discontinue selling its line of fast-drying epoxy. The company is also required to take other steps that are designed to prevent the kind of accident that killed Milena Del Valle, 38 of Jamaica Plain, MA, including the recall of all of its fast-setting epoxy now in the field and sending a warning of such dangers to all past users of the product. Further, Powers agreed to conduct no business with state and local governments until Jan. 1, 2012. The settlement marked a milestone in the state government's efforts to recoup losses for taxpayers because of shoddy work on the $15-billion Big Dig tunnel and highway project. So far, the state, in conjunction with the federal government, has recovered almost $550 million from contractors for the ceiling collapse, leaking tunnel walls, and other defects. The federal government helped pay for the project.