In the arid landscape of Henderson, Nevada, just a short 10-mile hop from Las Vegas, sat the PEPCON plant. Alongside its neighbor, Kerr-McGee, the two facilities represented the only American producers of ammonium perchlorate (AP), a vital component in the solid propellant rocket boosters used for the Space Shuttle, military weapons, and other rocket programs. Besides AP, the plant also produced other perchlorate chemicals and had a high-pressure gas transmission line running beneath it.
Following the tragic Space Shuttle Challenger disaster in January 1986, the grounded Space Shuttle fleet caused an excess of product, which was stored in aluminum bins at the PEPCON plant. This included around 4,500 metric tons of the finished product at the time of the disaster.
In the vicinity, you would find the Kidd & Company marshmallow factory just 500 feet away and a gravel quarry 3,000 feet to the west. The nearest residential buildings were about 1¾ miles away.
Fire and Explosions
There have been several theories about the cause of the fire and explosions at the PEPCON plant, but the Clark County Fire Department (CCFD) did not issue a formal report. Instead, they issued a press release that was incorporated into a United States Fire Administration (USFA) report. A separate report was issued by the United States Department of Labor (USDOL) in collaboration with the Division of Occupational Safety and Health (DOSH).
On that fateful day, the fire originated around a drying process structure at the plant. According to the USFA report, a windstorm had damaged a fiberglass structure, and employees were using a welding torch to repair it. The welding activity ignited a fire in the fiberglass material that spread rapidly, fueled by nearby ammonium perchlorate residue.
The USDOL report, however, challenged this theory. It relied on eyewitness testimonies and scientific burn tests, stating that welding operations had taken place somewhere between 30 and 90 minutes prior to the discovery of the fire. The report claimed that the possibility of transferring hot molten metal over 70 feet to the batch dryer was considered extremely remote.
The flames eventually spread to 55-gallon plastic drums containing the product. The USFA report described the first of a series of explosions occurring in the drums about 10 to 20 minutes after ignition. The USDOL report, on the other hand, detailed the fire’s rapid spread and subsequent growth to other buildings, primarily due to the highly combustible fiberglass reinforced siding panels and the close spacing of adjacent buildings.
The first detonation, which caused damage to the surrounding structures and batch dryer, had a yield estimated to be the equivalent of between 37 and 90 pounds of TNT. The USDOL report also mentioned evidence suggesting that natural gas leaks were present in the plant, which may have contributed to the disaster.
As the fire continued to spread, the USFA reported a total of seven explosions during the accident, with the two largest explosions producing seismic waves measuring 3.0 and 3.5 on the Richter scale. The largest explosion had an estimated yield of 0.25 kiloton TNT equivalent, similar to a 1.0 kiloton nuclear explosion in free air.
The USDOL concluded that the initiation mode of the fire was undetermined and suggested possible ignition sources such as smoking, sparking of electrical equipment, or frictionally ignited gas.
Seventy-five people managed to escape the disaster, but two were killed in the last two larger explosions: Roy Westerfield, PEPCON’s controller, who stayed behind to call the CCFD, and Bruce Halker, the buffer zone around the plant. The new facility was designed with state-of-the-art safety features and processes to prevent a similar disaster. The lessons learned from the PEPCON incident have been incorporated into the design, operations, and safety protocols at the new facility.
The Kidd & Company marshmallow factory, which was destroyed in the explosions, was rebuilt at a new location. The company instituted new safety measures and policies in response to the disaster. The gravel quarry near the PEPCON plant also suffered significant damage, but it was eventually repaired and resumed operations.
The city of Henderson, the residents, and the surrounding communities were deeply affected by the disaster. Many people lost their homes, businesses, and possessions, while others suffered physical and emotional injuries. The community came together to rebuild, provide support to those affected, and implement new safety measures to prevent future disasters. Schools, businesses, and other organizations in the area now participate in regular emergency preparedness drills and training exercises.
The PEPCON disaster served as a wake-up call for the need for greater oversight and regulation of the chemical industry. In response to the incident, the U.S. Environmental Protection Agency (EPA) and the Occupational Safety and Health Administration (OSHA) increased their scrutiny of chemical facilities, implementing stricter regulations and more frequent inspections. The Chemical Catastrophe Prevention Act and Nevada’s Chemical Accident Prevention Program are just two examples of the legislative efforts to improve safety in the industry.
Lessons learned
The PEPCON disaster highlighted several important lessons for the chemical industry and emergency responders. Among these are:
- Proper storage and handling of hazardous materials: The large amount of ammonium perchlorate stored at the PEPCON facility contributed to the severity of the disaster. Ensuring that hazardous materials are stored and handled according to established safety guidelines can help prevent accidents and reduce the potential for catastrophic events.
- Facility design and location: The close proximity of the PEPCON plant to other businesses and residential areas contributed to the widespread damage and injuries resulting from the explosions. Chemical facilities should be located in isolated areas, with buffer zones to minimize the potential impact on surrounding communities.
- Emergency preparedness and response: The response to the PEPCON disaster highlighted the importance of proper emergency planning and coordination among emergency responders. Regular training and drills can help prepare emergency personnel to respond effectively to chemical incidents.
- Regulatory oversight: The PEPCON disaster underscored the need for greater regulatory oversight of the chemical industry. Improved regulations and more frequent inspections can help identify potential hazards and ensure that facilities are operating safely.
- Community awareness and involvement: The PEPCON disaster served as a reminder that communities located near chemical facilities should be aware of the potential risks and involved in emergency planning efforts. Greater community engagement can help improve emergency preparedness and response, as well as promote a culture of safety within the industry.
In conclusion, the PEPCON disaster was a tragic event that resulted in significant loss of life, injuries, and property damage. However, it also served as a valuable learning opportunity for the chemical industry, emergency responders, and communities. The lessons learned from this disaster have led to improved safety measures, regulatory oversight, and emergency preparedness, ultimately helping to prevent future incidents and protect the lives and well-being of those who live and work near chemical facilities.
