A new report from Con Ed reveals that "a tiny clump of leak-sealing epoxy" caused the blast in a Midtown steam pipe earlier this year. The pipe, at Lexington and 41st Street, ruptured on July 18, causing millions in damage; one person died of a heart attack while two people in a tow truck above the pipe and subjected to 400-degree steam were critically burned.

Con Ed, as well as the city, is facing lawsuits from the blast victims and area businesses who say the utility's negligence played a part in the explosion. It was suggested earlier that a "crack-like flaw" caused the explosion; Con Ed dismissed and clarified the claim, saying a weld "in no way contributed to the rupture." Now, Con Ed's report seems to reverse that. From the Daily News:

Con Edison crews pumped the epoxy into a nearby leak four months before the July 18 blast, but no one noticed some of it seeped into the "steam trap" valve - leading to catastrophe when the 20-inch steampipe filled with water.

"It's a combination of clogged traps and elevated water levels underneath the ground," Con Ed spokesman Michael Clendenin said last night. "We think the clog was from an epoxy resin that was used to seal a flange."

The clump of resin led to a catastrophic condition called "water hammer." That blew the 87-year-old pipe wide open at E. 41st St. and Lexington Ave...Clendenin said Con Ed is changing its rules for fixing leaky flanges and for inspecting steam traps - and replaced all 1,654 steam traps in its system as a precaution, but didn't find any similar epoxy clogs in them.

In August, the News reported that the pipe's steam trap may not have been working. Kenneth Thompson, representing Gregory McCullogh, the tow truck driver who had burns on 80% of his body, and his passenger Judith Bailey, said to the News, "How do we know for sure that there wasn't any epoxy in any of those other steam traps? Are we supposed to take Con Ed's word for it?"

Photograph of the red tow truck by sidewalk_story on Flickr