The harrowing story of five men who were sent into a dark, airless, miles-long tunnel, hundreds of feet below the ocean, to do a nearly impossible job with deadly results A quarter-century ago, Boston had the dirtiest harbor in America. The city had been dumping sewage into it for generations, coating the seafloor with a layer of black mayonnaise. Fisheries collapsed, wildlife fled, and locals referred to floating tampon applicators as beach whistles. In the 1990s, work began on a state-of-the-art treatment plant and a 10-mile-long tunnel its endpoint stretching farther from civilization than the earth s deepest ocean trench to carry waste out of the harbor. With this impressive feat of engineering, Boston was poised to show the country how to rebound from environmental ruin. But when bad decisions and clashing corporations endangered the project, a team of commercial divers was sent on a perilous mission to rescue the stymied cleanup effort.Five divers went in; not all of them came out alive. Drawing on hundreds of interviews and thousands of documents collected over five years of reporting, award-winning writer Neil Swidey takes us deep into the lives of the divers, engineers, politicians, lawyers, and investigators involved in the tragedy and its aftermath, creating a taut, action-packed narrative. The climax comes just after the hard-partying DJ Gillis and his friend Billy Juse trade assignments as they head into the tunnel, sentencing one of them to death. An intimate po