DES MOINES, Iowa (AP) -- A sewer pipe ruptured Monday at a construction site, killing two workers and injuring 10 others, fire officials said.
Fire officials said the workers likely suffocated because the toxic sewer gas deprived them of oxygen.
The workers were in a 16-foot trench at an industrial area on the east side of Des Moines. Acting Fire Chief Doug Rubin said they had climbed down a ladder to get on a platform when they were overcome by fumes. Some fell into the water.
"When they went down in the hole, they go down with hardhats and lights, not necessarily any breathing equipment," Rubin said. "This is something they do all the time. This is obviously an oddity, what happened today."
Hydrogen sulfide gas is produced by the decomposition of organic materials such as sewage, said Assistant Chief James Mason said.
"These workers were likely not overcome by the gas; however, a lack of oxygen caused them to go unconscious" he said. He said both victims were found in the water at the bottom of the pit.
Five of the injured were firefighters; four of them were taken to a hospital where they were treated and released. Conditions on the others weren't immediately available.
City officials said the two dead workers were employed by Insituform Technologies Inc., a company specializing in the repair of city sewers.
"This is a tragedy for all of us," said Tony Hooper, president and chief executive of Insituform.
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