Posted on 01/11/2025 6:40:36 PM PST by TigerClaws
Air tankers are dropping thousands of gallons of red flame retardant in the hills around Los Angeles as firefighters attempt to limit the devastation from multiple wildfires.
Images of vivid red clouds enveloping trees and scrubland prompt two questions: What is it, and what’s in it?
“It’s primarily a product called Phos-Chek LC95, which is sold by a company called Perimeter,” Daniel McCurry, an associate professor in civil and environmental engineering at the University of Southern California, tells NPR.
“It’s been used for decades by the Forest Service,” he says. “It’s one of maybe only two products currently approved for aerial use by the Forest Service.”
Air tankers and chemical fire retardants have been used since the 1950s, allowing firefighters to reach difficult spots. The U.S. Forest Service says retardants are used to “slow the rate of spread by cooling and coating fuels, depleting the fire of oxygen, and slowing the rate of fuel combustion as the retardant’s inorganic salts change how fuels burn.”
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So, what’s in Phos-Chek?
“It’s basically a mixture of water, fertilizer, and then the red color that you see is just rust,” McCurry says. In the wild, the color fades over time with exposure to sunlight.
“You might see a gum or thickening agent just to change the viscosity, how sticky this stuff is,” McCurry says. Thickeners also keep the material from drifting off-target, he adds, “But the business end of it really is ammonium phosphate fertilizer.”
For anyone who’s heard of fertilizer being used in explosives: That’s ammonium nitrate. Phos-Chek commonly contains two types of salt: diammonium phosphate ([NH4]2HPO4) and ammonium polyphosphate ((NH4PO3)n).
Along with its use as a fertilizer (providing nitrogen and phosphorous to plants), you often see ammonium phosphate in crystal-making kits that are popular with children. So, how does Phos-Chek stop fires from spreading?
Under normal conditions, cellulose in plant matter decomposes as it’s heated, producing flammable compounds. Phos-Chek’s maker says the reaction between the retardant and cellulose consumes heat energy from the approaching fire and produces non-flammable carbon material.
The goal is to slow or stop the fire’s spread, especially if the area includes homes or other structures.
“They don’t tend to drop [retardant] directly in the center of an ongoing fire,” McCurry says. “They tend to drop kind of at the barrier of it because they’re trying to prevent it from spreading. And the reason that these products are kind of useful for that potentially is that the active ingredient is not water. Right? It’s the fertilizer. So even after the water evaporates, you still have that red stripe there for days or weeks.”
Big air tankers can drop up to 9,400 gallons of Phos-Chek onto trees and other potential fuels. The massive quantities have spurred McCurry and other researchers to consider potential harms from the material. But McCurry says people in a fire zone likely have more pressing worries.
“In terms of immediate concern, the main thing I’d be worried about, regardless of whether there’s fire retardant used or not, is just air pollution — like particulate matter,” he says. “If you’re walking around in an area that’s been burned, it’s probably still very smoky. So it’d be a good idea to wear a respirator.”
Is Phos-Chek safe?
Due to environmental concerns, the Forest Service has a mandatory ban on aerial retardant drops in sensitive areas such as waterways and endangered species habitats (map). That ban is in effect “except when human life or public safety are threatened.” Using retardants in restricted areas must be reported for possible remediation.
Phos-Chek doesn’t include any substances flagged by California’s Proposition 65 list of materials that are known to cause cancer and other harms, according to its maker.
The Forest Service’s specifications for wildfire retardants ban PFAS, known as “forever chemicals,” along with other unacceptable compounds.
Last year, McCurry and his colleagues published a study suggesting some fire suppression products, including Phos-Chek, can contain toxic heavy metals such as cadmium and chromium. The Forest Service says heavy metals aren’t added to fire retardants, “But may be present as naturally occurring impurities in the retarding salts (which come from the same source as crop fertilizers),” Boise State Public Radio reported last November.
As for the air tankers’ operations over smoldering hillsides, the most immediate danger would seem to be to the aviators.
“It’s a really heroic job,” McCurry says of the pilots — many of them former military, he says — who guide massive planes through low-altitude drops over challenging terrain. “You know, some of those guys die every year.”
Between 2000–2013, there were 78 aviation deaths related to fighting wildfires, according to a 2015 report by the Centers for Disease Control and Prevention.
The pink/often rust-red stuff they drop from planes onto fires is heavy. From experience I can say you don’t want to get hit on the noggin with that stuff. As a newbie on a fire line many, many years ago, my more experienced peers let me learn that lesson the hard way. Did’nt get injured but it knocked my helmet off and knocked me to the ground.
Forestry fire fighting in northern California was my summer-fall job between high school and college.
DEI at work. pic.twitter.com/lx94rhpFYk— Patrick Bet-David - CEO of Valuetainment (Parody) (@notPBD) January 9, 2025
I saw footage of it dumped on a car and it ain’t light for sure. Destroyed the car.
Actually we were cutting a line just to one side of a ridge and the plane was approaching from one direction, behind us, and was to drop its load just up and over ahead of us. All the other guys knew what to expect and dropped to the ground, letting me stand and “admire” the drop about to take place. They all chuckled as they stood up and I got up to go get my helmet, which lay about ten feet in front of me.
Probably gat juice or something.
Which is heavier?
A pound of fire retardant or a pound of feathers?
“A pound of fire retardant or a pound of feathers?”
A pound of feathers will not make it to the ground anywhere near as intact as much as a pound of retardant. The feathers will disperse and float about extremely more.
Pixie dust?
Go to 1:20 in to see the effects of a direct drop on a vehicle:
https://www.youtube.com/watch?v=ONdSoiI4zIA
Ha!
Gender reveal dust?
California couple whose gender-reveal party sparked a wildfire charged with 30 crimes
https://www.theguardian.com/us-news/2021/jul/21/couple-gender-reveal-party-wildfire-charged
Sounds like a trick question so I am going with the nonobvious choice, the feathers. Where do I get my prize?
Agent orange?
Does Nancy Pelosi own stock in the company?
Napalm.
🔥
Knowing enviro wackos, this is likely ‘watered down’ to protect animals. Guarantee you it could be many times more effective if made by true scientists.
All carbon material is flammable. What this lying puke really means is it produces atmospheric carbon dioxide gas, but can't say that as it might wake up some man-made climate change hoax dupes.
Related: The new Senator from Montana, Tim Sheehy (who defeated Tester), started up Bridger Aerospace (in Montana) to run firefighting aerial tankers. He was very successful at it after his military career.
What does ACGIH say about it? Or check out its owm MSDS.
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