1988

PEPCON^® Explosion

When the space shuttle Challenger was destroyed during liftoff in 1986, the whole NASA shuttle program came to a halt for more than two years while the deadly accident was investigated. One of the lesser-known effects of this hiatus was the accumulation of solid rocket propellants at their manufacturing sites. With no rocket boosters being made, several million pounds of ammonium perchlorate, a component of their solid fuel propellants, were stored at the PEPCON chemical company in the Nevada desert.

It’s in everyone’s best interest for any perchlorate facility to be located as far away from everything else as possible. Perchlorates feature chlorine atoms in their highest oxidation state, ready to oxidize anything they come in contact with. They are notoriously treacherous compounds, unforgiving of sloppy handling, and known to cause fires and explosions. The large amount of oxygen carried on the perchlorate anion means that once a fire starts, it doesn’t have to rely on a supply of air. This feature has long made perchlorates a key ingredient of solid rocket fuel mixtures (and a common ingredient in fireworks manufacturing, which is a disturbingly similar field in many ways!).

On May 4, 1988, what may have been a welding accident started a fire at PEPCON, and the workers (fully aware of the potential for disaster) tried frantically to put it out. But the flames spread to a storage building packed with perchlorate-filled drums, causing the employees to flee for their lives. Local responding firemen parked a mile away, but all the windows of their trucks were blown out when the main stockpile of ammonium perchlorate exploded. A neighboring building and employees’ vehicles were destroyed, and other buildings nearby suffered extensive damage. The gigantic blast threw a visible shock wave across the desert and was measured by distant seismographs at about 3.5 on the Richter scale. Only two people were killed, but hundreds of others, as distant as ten miles away, were injured by blown-in window glass and the effects of the shock wave. It was a dramatic demonstration of the unharnessed power of chemicals that humans may think they have under control.

SEE ALSO Gunpowder (c. 850), Nitroglycerine (1847), Oxidation States (1860)

The 1986 explosion of the Challenger space shuttle brought a halt to manned space launches in the United States while the cause was tracked down, but the resulting oversupply of solid rocket fuel created its own problems.