Originally published on NEWS3 Las Vegas
LAS VEGAS (KSNV) — The largest chlorine gas leak in North America happened 29 years ago, and it was right here in the Las Vegas Valley.
The first clue that something was wrong came in the early hours of May 6, 1991, when someone driving through the area that is today the I-215/I-515 interchanged pulled over to call 9-1-1.
“All units responding, we have a smell of chlorine at State Route 147 and U.S. 95,” called out a dispatcher on the Fire Department radio frequency.
“It doesn’t take much on a big chlorine leak to wipe out a lot of people,” remembered former Henderson firefighter Don Griffie in 2013. “You just hope the wind’s blowing the right way.”
“We’re gonna check Pioneer Chemical out,” radioed a Henderson Fire unit in response to the original call.
Pioneer Chlor Alkali in the BMI Industrial Complex near downtown Henderson was running an operation that in some ways was not that different from a common high school science experiment in electrolysis – but on a massive scale.
“When they make chlorine, they take salt from the Great Salt Lake up in Utah and they take water from Lake Mead,” explained Clark County Fire Department Hazardous Materials Specialist Richard Brennan in 2013. “And they mix it into a brine solution. Saltwater, basically. And then they run a cathoid and an anoid, and they run DC voltage, which they get from the dam. And then they basically separate.”
On that night though, something went wrong.
“What happened there was they had one of their chill lines that actually blew out,” continued Brenner. “And started mixing with chlorine and started making hydrochloric acid.”
Over 70 tons of chlorine liquid turned to gas, spreading a greenish haze. Thousands of people were evacuated, and 200 were taken to local hospitals, with 30 admitted.
“Right now, we haven’t really had to do much at all except with two or three of the patients have what they call bronchospasm,” UMC Emergency Director Dr. Charles Zumpft told News 3 later that day. “Their lung tubes try to collapse because of the irritation. And they’ve responded real well with some inhalation medicines. And they’ve been able to go home after they’ve been treated with that.
As the leak was capped, sunlight and breezes dissipated the cloud. Firefighters in HazMat suits went through decontamination and returned to regular duty. But Henderson remained jittery.
“The County Fire Department got so many calls that they stationed a unit out here for the rest of the day,” reported News 3’s Tonia Ellis. “Although coming out here and finding nothing may seem like unnecessary work, they have to take every call seriously, because they never know which one will be the real emergency.”
In the almost three decades since that leak, there has not been another emergency along those lines. The name is gone from Southern Nevada, though the factory is still there.
“What’s called Pioneer is now Olin,” said Brenner. “They still manufacture chlorine gas. They are manufacturing other products [like] bleach.”
Olin still manufactures bleach in Henderson, but they ceased chlorine production here in 2016.
In the days following that 1991 industrial accident, a second story developed out of the way dispatchers responded to initial reports and it became a bit of a scandal. That’s the subject of next week’s Video Vault.