Friday, May 11th is the 42nd anniversary of one of the largest hazardous material spills in Houston’s history. Just after 11:00 a.m. on that fateful day in 1976, a semi-tractor trailer rig carrying more than 7,000 gallons of anhydrous ammonia plunged off of a freeway ramp, causing the contents of the tanker to spill onto the roadway below and sending some of the poisonous gas airborne.
According to an article appearing on the Chron.com website, seven people lost their lives and 200 more people were injured in the spill. According to Steve McCann, who witnessed the accident as it happened, it could have been much worse. McCann first heard the sound of metal grinding against metal. “I looked up as I went under the loop and saw the truck bouncing off the guardrail,” McCann read an interview he gave to The Houston Post just after the accident.
In an interview with Chron.com, McCann recounted that he saw an explosion as the truck came down. McCann had pulled over because a piece of the truck’s debris had hit the rear end of his vehicle. He saw the cloud of white smoke, first thinking it was chlorine. He held his breath and ran as far and as hard as he could to get away from the cloud of potentially lethal gas.
Investigators would later determine that the driver of the truck had lost control of his vehicle, struck a support beam, sending it off the ramp of the loop. The National Transportation Safety Board would later determine that the driver had been traveling at an unsafe speed. Anyone who happened to be too close to the cloud of ammonia would likely have died from exposure to the gas. Six died at the scene of the crash, and a seventh died shortly afterward. Anyone who was injured and yet survived the crash has had ongoing health challenges due to permanent damage to their lungs.
At the time of the crash, the Houston Fire Department did not have a hazmat team. It is because of this deadly accident 42 years ago that no hazardous materials in such large quantities are permitted inside the 610 loop.