FYI...this should be good for the debate.
NTSB Advisory
National Transportation Safety Board
Washington, DC 20594
July 5, 2007
NTSB MEETS TO ADOPT FINAL REPORT ON CEILING COLLAPSE IN BOSTON'S BIG DIG TUNNEL
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I don't know, it appears to me that the epoxy company, Powers Fasteners may have culpability here.
1. If the standard material was approved and the fast set (the story stated that fast set was not recommended to suspend loads overhead) material was sent to the job to secure ceiling panels...
http://www.boston.com/news/traffic/bigdig/articles/2007/05/03/big_dig_job_may_have_used_wrong_epoxy/
Latest News on Epoxy
Boston Globe
Big Dig job may have used wrong epoxy
Total of bolts affected not clear; probers ask who knew
By Scott Allen and Sean P. Murphy, Globe Staff | May 3, 2007...