John J. Keaveney, the on-site safety officer for the Interstate 90 connector in Boston, Mass., warned his bosses at contractor Modern Continental Construction that the tunnel ceiling could collapse because the bolts could not support the heavy concrete panels, reports Boston.com. He also feared for his conscience if someone died as a result of continuing their use.Boston.com reports that during the current investigation into the Big Dig ceiling collapse that crushed Milena Del Valle to death two weeks ago, a recently found two-page memo from 1999 shows that Keaveney wrote to Robert Coutts, senior project manager for Modern Continental, telling him he couldn\u2019t comprehend how the structure being used could stand the test of time.Keaveney added, "Should any innocent state worker or member of the public be seriously injured or even worse killed as a result, I feel that this would be something that would reflect mentally and emotionally upon me, and all who are trying to construct a quality project."Boston.com reports that in an interview last night, Keaveney said after he raised concerns, his superiors at Modern Continental and representatives from Bechtel\/Parsons Brinckerhoff, the private sector manager of the Big Dig, tried to reassure him, telling him that such a system had been tested and was proven to work.Keaveney also told Boston.com that he raised concerns directly to Bechtel\/Parsons Brinckerhoff in subsequent conversations. Representatives from the company told him they were doing the work to design specifications and that the ceiling would hold.Andrew Paven, a spokesman for Bechtel\/Parsons Brinckerhoff, declined to comment to The Boston Globe last night. Efforts by the paper to reach representatives of Modern Continental were also unsuccessful.The Globe reports that Keaveney was not the only person to voice concerns about the system for securing concrete ceiling panels. He also observed water dripping from the holes that construction workers drilled before the epoxy and bolts were inserted to fasten the panels. He asked whether epoxy was suitable for a wet environment and how long it could withstand the pressure.He voiced many other concerns, including bolts and tiebacks having rust before installation, and that the bolts would be subject to horizontal and lateral movement when the vent fans went on, Boston.com reports. His memo also said that while workers were doing the project according to specifications, he worried that when the state took control of the tunnel, maintenance and vigilance would be neglected.Read more about his memo and the investigation into the Big Dig tunnel collapse.Compiled by Paul KersteinKeep checking in at our Security Feed for updated news coverage.