At 10:07 a.m. central daylight savings time on Monday, October 17, 1994, a natural gas explosion and fire destroyed a one-story, wood frame building in Waterloo, Iowa. The force of the explosion scattered debris over a 200-foot radius.
Six persons inside the building died, and one person sustained serious injuries. Three persons working in an adjacent building sustained minor injuries when a wall of the building collapsed inward from the force of the explosion. The explosion also damaged nine parked cars. A person in a vehicle who had just exited the adjacent building suffered minor injuries. Additionally, two firefighters sustained minor injuries during the emergency response. Two other nearby buildings also sustained structural damage and broken windows.
We determined that the probable cause of the natural gas explosion and fire in Waterloo, Iowa, was stress intensification, primarily generated by soil settlement at a connection to a steel main, on a 1/2-inch polyethylene pipe that had poor resistance to brittle-like cracking.
As a result of this investigation, we issued 23 new recommendations. We issued recommendations to:
- The Research and Special Programs
Administration
- The Gas Research Institute
- The Plastics Pipe Institute
- The Gas Piping Technology Committee
- The American Society for Testing and Materials
- The Amercan Gas Association
- MidAmerican Engery Corporation
- Continental Industries
- Dresser Industries
- Inner-Tite Corporation
- Mueller Company
