The screams. The bodies lying across the freeway. The people trying to run away from a toxic cloud before collapsing to the ground.
Fifty years later, retired Houston firefighters say they still remember every detail from one of the deadliest disasters in Houston history.
“It looked like a war zone,” retired Houston firefighter Brad Rilay said.
On May 11, 1976, a tanker carrying more than 7,000 gallons of anhydrous ammonia plunged off the 610 West Loop ramp and crashed onto the Southwest Freeway below.
The impact ripped open the tanker, sending a massive cloud of toxic ammonia into the air during the middle of the morning rush.
Seven people died.
Dozens more were injured.
And the disaster changed the Houston Fire Department forever.
Rilay was only 20 years old when he responded to the scene.
That morning had started like any other shift.
Rilay said he and a district chief had just finished another call farther down the Southwest Freeway when dispatchers warned crews about a tanker crash involving ammonia near the West Loop interchange.
As they drove toward the area, traffic completely locked up.
Rilay said he ended up driving against traffic on the freeway shoulder just to reach the scene.
When they arrived, he said the destruction was overwhelming.
“Man, it looked like a war zone, you know, the parts of the truck scattered everywhere, and the truck driver’s body was lying in the middle of the road,” Rilay said.
The crash scene stretched across the freeway.
Pieces of the tanker and destroyed vehicles were scattered throughout the interchange.
Victims were already dying from exposure to the fumes.
Rilay remembers immediately finding several people on the ground struggling to breathe.
“We immediately came across three people, one man who had already died, and there were two who were struggling to breathe,” he said.
At the time, Houston firefighters had little training on hazardous material incidents and almost no specialized equipment to handle a chemical release that large.
Firefighters grabbed an air pack from the chief’s car and tried helping victims breathe through the mask.
“But I don’t know how much good that did,” Rilay said quietly.
What stayed with him most was the helplessness.
“You know, have a brown mucus coming out of their mouth and their nose, and the feeling of not being able to help them,” Rilay said.
,As the ammonia spread across the freeway, drivers abandoned their vehicles trying to escape.
Some never made it far enough.
“The people who were forced to stop, they got out of the car and tried to get away from it,” Rilay said. “They probably made it 25 or 30 feet before they collapsed.”
The toxic cloud moved unpredictably across the freeway interchange.
Rilay described it as almost impossible to avoid.
“Yes, when we got there, the big, huge white cloud was just above the West Loop,” he said.
The danger wasn’t always visible.
“You could be standing there trying to help somebody, and all of a sudden you couldn’t breathe,” Rilay said.
Retired firefighter Bill Hand also responded to the scene that day.
Hand was working out of Station 1 downtown and helping transport additional air bottles to crews already fighting to rescue victims on the freeway.
By the time he arrived, much of the initial chaos had already unfolded.
But he remembers unknowingly walking into what he called an “invisible shield” of ammonia.
“It was like bam,” Hand said. “I mean, it just sets you back.”
At the time, firefighters did not fully understand how dangerous anhydrous ammonia could become after a crash.
“We really didn’t know what to expect,” Hand said.
Years later, Hand would learn the chemical had expanded rapidly after the tanker ruptured.
“It expands 800 times,” Hand explained. “So you had 800 tank trucks of gas that went off the freeway.”
The disaster exposed major weaknesses in Houston’s emergency response capabilities.
Back then, Houston did not have a dedicated hazmat team.
Firefighters responding that day were largely learning in real time while trying to save lives.
“We didn’t have a hazmat team,” Rilay said. “We didn’t have the equipment on the apparatuses and on the chiefs' cars as they do now.”
The deadly crash became a turning point for the department.
Hand later became one of the original members of Houston’s first hazmat team after fire leaders pushed to improve chemical emergency response training.
“I was part of the original team,” Hand said.
Houston firefighters began training directly with petrochemical companies and industrial emergency response teams throughout the region.
Hand said the department slowly built a specialized response program focused on chemical incidents, rescue operations, and firefighter safety.
He spent the remainder of his career focused heavily on hazmat response and training.
“I really pushed for training,” Hand said. “That’s how much I believe in it.”
Houston Fire Department Chief Muñoz says the lessons learned from the 1976 disaster helped shape the modern hazmat response system Houston uses today.
“Our hazmat teams are, I would consider them the best team in the country,” Muñoz told KPRC 2. “The training they do, the equipment we have, and of course, the support that we have.”
Today, Houston hazmat crews use specialized trucks, protective suits, air monitoring systems, chemical detection equipment, and advanced response protocols that firefighters in 1976 simply did not have access to.
Muñoz said departments from across the country often look to Houston’s hazmat teams for training and guidance.
Five decades later, both firefighters say the memories never disappeared.
Rilay says every trip through the Southwest Freeway interchange brings him back to that day.
“I think about it every time I go through that intersection,” he said.
Both men say they hope people understand dangerous chemicals are still moving through Houston every day.
And they warn drivers to stay alert around tanker trucks and chemical spills.
“Don’t drive through vapor clouds,” Hand said. “Our freeways are jammed with people; there’s a lot of hazardous materials out there.”