Ammonia, also known as anhydrous ammonia, is well known to be a dangerous chemical capable of inflicting severe chemical burns on an individual's air system and causing death. On May 11, 1976, people along US 59, or the Southwest Freeway, and Interstate- 610, or the loop, received first-hand information concerning the dangers of ammonia.
Around 11 a.m. on May 11, 1976, a Transport Company of Texas tanker truck carrying 7,509 gallons of anhydrous ammonia, or ammonia, hit a bridge rail on an overpass connecting the Southwest Freeway and the Loop. The truck went through the rail and ended up falling roughly 15 feet onto the Southwest Freeway.
Following the impact with the lower highway, the damaged truck released the vast majority of its cargo into the atmosphere. When the ammonia was released, there were around 500 people within a quarter of a mile of the spill. The ammonia in question vaporized almost immediately. It must not have been very humid that morning as the wind, at 7 miles per hour, gradually decreased the concentration at ground level. This is possible when it is not humid as ammonia is less dense than air. When there is water present in the air, the ammonia mixes with it and stays close to ground level. Within 5 minutes, the liquefied ammonia boiled off and the vapor cloud had completely dispersed.
As a result of the accident, 6 people lost their lives, 78 people were hospitalized with serious injuries, and 100 more sought medical attention for less severe injuries. Of the 6 deaths, 5 of them were attributed to inhaling anhydrous ammonia. All 178 injuries were also attributed to inhaling or exposure to the ammonia. All victims of the spill were within 1000 feet of the release site for the ammonia.
It has proven by this accident that those who stayed in their cars or office buildings had less of a chance of being injured severely by the ammonia. All of the people who were injured were outside of their vehicles or buildings. They either started out outside of their cars or got out to help. For this reason, it is recommended that people not rush into an ammonia spill without protective gear. Also, when helping people who have been hurt by ammonia, it is recommended that rescuers approach from upwind. This ensures a better chance of the ammonia having left the area already.
Source by Joseph Devine
