Two employees of Insituform Technologies Inc. were killed and five others injured July 8 when a sewer pipe ruptured at a construction site in Des Moines, Iowa.
Brian Buford, 19, and Dan Grasshoff, 25, drowned in a pit of water in a 16-foot trench after they were exposed to hydrogen sulfide, a common sewer gas.
A lack of oxygen caused the workers to pass out, said Michelle Lucas, marketing manager with Chesterfield, Mo.-based Insituform.
``Right now, we can't figure out what went wrong,'' she said by telephone July 11. She said Insituform had all the proper safety equipment on site, including oxygen. ``We're still interviewing to recreate [the scene], and the Occupational Safety and Health Administration has started its investigation.''
Lucas said the men were part of a traveling crew from St. Louis. The company has more than 60 crews working throughout the United States. All five injured workers were released from the hospital by July 11, Lucas said.
Insituform repairs pipe using a patented process. Work crews use water to force resin-impregnated tubes inside of old pipe, then cure the tubes with hot water to create a new plastic liner.