EASTER HAZMAT - 1983

Photo: Denver Fire Department

On Easter Sunday 1983, Denver's hazmat team used ingenuity to contain a spill from a ruptured railroad tank car that set off a poisonous plume. 

They employed a diesel snow blaster from Stapleton Airport to pour piles of a neutralizing soda ash on 20,000 gallons of nitric acid deposited on the grounds of the Denver & Rio Grande Western Railroad yard, Fire Engineering magazine reported.

A late season snowfall also helped dampen the effects, United Press International reported. 

According to a National Transportation Safety Board investigation of the accident: "The switch crew was moving 17 cars when a coupler broke on the 4th car, leading to an undetected separation of 150 feet between the 3rd and 4th cars.

"The engineer, responding to a hand lamp signal from the foreman, accelerated the locomotive, with a caboose, an empty freight car, and a loaded tank car coupled ahead.

"The loaded tank car impacted a fourth car at a speed of about 10-12 mph."

A fire accompanied the spill.

Billows of the chemical prompted the evacuation of as many as 9,000 people, based on NTSB estimates.

Fumes threatened downtown Denver and closed Interstates 25 and 70.

"The one tremendous break that we got was that the wind was blowing to the south down the Platte River Valley, which acted to contain the hazardous yellow cloud in an area that is very sparsely populated," Denver Fire Chief Myrle K. Wise wrote in Fire Engineering.

United Press International reported: "Civil Defense sirens, police with loudspeakers and radio broadcasts were credited with giving residents quick warning so they could escape."

Nonetheless, 34 people were injured, the NTSB said. 

The New York Times reported: "Many people appeared to ignore the hazard. Several churches in central Denver went ahead with Easter morning services as scheduled."

Easter Sunday 1983 fell on April 3.

Initial Fire Department Response - 4:11 a.m.

Pumpers 9, 4, 7
Truck 4
District Chief 6

Hazmat Response
Station 6, Squad 1

According to The Chemical Company: "Nitric acid is used in the production of ammonium nitrate for fertilizers, making plastics, and in the manufacture of dyes. It is also used for making explosives such as nitroglycerin and TNT."