It’s a familiar scene in today’s wildfire season: Before sunrise, flames erupt in the hills above Los Angeles, driven by dry winds and brittle fuel. Within minutes, neighborhoods are under threat. Even before the first evacuation order is issued, helicopters are in the air — dropping lines of red retardant in a race to slow the fire’s advance and protect homes in its path.
For helicopter pilots, the fight against wildfire is increasingly being shaped by what they carry onboard. Beyond water, many now deploy advanced chemical agents — fire retardants and suppressants — that extend their reach and improve effectiveness in conditions that are hotter, drier, and more volatile than ever before. These tools are helping helicopter crews do more than contain fires. They’re protecting homes, habitats, and entire communities.
Though often mentioned in the same breath, fire retardants and fire suppressants serve different tactical roles. Retardants, like Perimeter Solutions’ Phos-Chek, are generally dropped ahead of a fire to treat vegetation and form a chemical barrier. The goal is to stop a fire from advancing by making unburned fuels non-flammable. Suppressants, such as BlazeTamer380 and GelTech’s FireIce, are used more directly — applied onto active flames to knock them down fast and support rapid response.
“Retardants are meant for delaying the spread, especially when it takes time for ground crews to arrive,” explained Melissa Brooks, managing director at BioCentral Laboratories, which makes BlazeTamer380. “A suppressant is used when aircraft are deployed right away and the goal is aggressive initial attack.”
Phos-Chek, a phosphate-based retardant, has been used in aerial firefighting for decades and remains a core tool in wildfire strategy. It works by coating vegetation and rendering it non-flammable by chemically altering it into a carbon-like layer that doesn’t support combustion.
“There will be a short amount of time when the fire will burn, but its intensity is reduced and the spread slowed, giving firefighters more time to extinguish the flames,” said Melissa Kim, vice president of research and development at Perimeter.
Long-term retardant is used to create a fire break — but Kim said Phos-Chek is also effective as a direct attack tool.
“Since retardant does not rely on the water it contains, it can protect fuels from wildfire for weeks to months, until washed away by rain,” Kim said.
Suppression tools, by contrast, focus on enhancing water delivery. They are typically deployed directly onto active flames to cool and extinguish the fire quickly.
BlazeTamer380 uses a polymer-based liquid formula that binds water molecules together, allowing aircraft to release a more cohesive stream that holds together in windy conditions and reaches deeper into canopies.
It creates a blanket effect when dropped from an aircraft, helping to get “the bulk of that water onto the ground, where it can do the most good,” Brooks said.
FireIce uses a different approach — a powder that, when mixed with water, forms a dense matrix of water-filled bubbles that cling to fuels and create a physical barrier.
“It doesn’t just thicken water,” said Ed Kleiman, GelTech’s chief technology officer. “It encapsulates the fuel in a blanket of water that’s non-receptive to ignition.”
For helicopter operators, compatibility and turnaround time are critical. All three products are approved for aerial use and can be mixed in ground tanks or injected directly into onboard systems. Suppressants like FireIce and BlazeTamer380 are often loaded via mobile dip tanks placed close to the fire line. Retardants like Phos-Chek are often mixed at mobile retardant bases (MRBs), allowing helicopters to reload quickly between drops.
“[BlazeTamer380] can be used in helicopters with buckets or tanks, and even scoopers and large air tankers,” Brooks said. “There are no compatibility or corrosion issues, which is critical given the sensitivity of aircraft components.”
Kleiman noted that FireIce can be used both ways — as a direct suppressant and a short- to medium-term retardant. That dual-use ability has made it a favorite among agencies performing both suppression and pre-treatment for backburn operations.
“We use it for direct suppression to knock down active flames, but also to build a fire line and create a chemical barrier,” Kleiman said. “It’s the same product, mixed at the same ratio with water, but deployed in different ways depending on the mission.”
Its colored formulation also provides a visual indicator from the air — critical for precise line-building during pre-treatment and indirect attack.
Retardants like Phos-Chek are now also being used in innovative ways. In California, Perimeter Solutions supports the Quick Reaction Force (QRF) — an aerial firefighting program that uses night vision goggle (NVG)-equipped helicopters and mobile MRBs to operate 24/7. In its first season alone, the QRF responded to 50 wildfires and dropped nearly three million gallons of Phos-Chek.
On the ground, the science continues to evolve. BioCentral is developing an alternate version of BlazeTamer380 to extend the range of hand crews working in drought conditions.
“We’re trying to help hotshot crews and other firefighters stretch their water supplies,” Brooks explained. “This could be a game-changer for areas facing drought or with limited water access.”
Broader Applications
Meanwhile, GelTech is exploring non-wildland applications for its products, including structure protection during high-rise fires and industrial hazard zones.
“We’re using FireIce in extreme-risk environments — fires over 5,000 degrees — where you just can’t send in a ground crew,” Kleiman said.
With growing scrutiny over chemical use in wildfire zones, environmental safety is a top concern.
All three companies emphasized the U.S. Forest Service Qualified Products List (QPL) as a benchmark of product safety. Phos-Chek has also undergone a full environmental impact statement (EIS), confirming its safety for human health and endangered species.
BlazeTamer380 has passed U.S. Department of Agriculture (USDA) and biological oxygen demand (BOD) testing to confirm minimal impact on aquatic life. “Our polymers are actually used in global wastewater treatment and agriculture,” Brooks said. “We’re very conscious about what’s going into the environment.”
FireIce also meets stringent Environmental Protection Agency (EPA) and Food and Drug Administration (FDA) standards, using food-grade ingredients. “Not only is it environmentally inert, but it’s safe enough to be in contact with food,” Kleiman noted.
Still, challenges remain. A fragmented procurement system can slow deployment, resulting in promising products being underutilized.
“In California, we had contracts and bases ready to go, but communication broke down during a major fire event,” Brooks said. “It’s something we’re working hard with agencies to fix before the next season.”
Compatibility and corrosion concerns have also limited the use of certain retardants in fixed-tank aircraft. Perimeter addressed this with its corrosion-resistant Phos-Chek 259-Fx, which is the only retardant qualified for use in fixed-tank helicopters.
Cost and color are also under debate. Some agencies prefer colored drops for better visibility during operations, while others aim to reduce dye use due to added expense or environmental concerns.
Phos-Chek’s fire retardant uses a fugitive red pigment that fades within weeks when exposed to sunlight and weather. The added color helps pilots visually track their drop lines and ensure there are no gaps in coverage — giving ground crews more time to suppress the fire.
In contrast, suppressants like BlazeTamer380 are intentionally colorless. “The fire is the visual indicator,” Brooks explained. “Once you drop it, you’re either seeing red flames or black earth — color in the product wouldn’t help much.”
For helicopter pilots flying with programs like the QRF or supporting state-level wildfire agencies, chemical tools like fire retardants and suppressants offer more than just tactical support — they provide confidence. These products are expanding the role of rotor crews, increasing their impact not only on the front lines but also in preventative operations.
FireIce has helped protect homes and businesses during recent wildfires in the Los Angeles area. Phos-Chek has been credited by homeowners during California’s Apple Fire and Arizona’s Diamond Fire. Meanwhile, BlazeTamer380 is being used across the U.S., not only as a suppressant during active wildfires but also in prescribed burns to reduce fuel loads ahead of peak fire season.
By extending the effectiveness of every drop, these agents allow helicopters to do more than respond — they help shape the outcome. That added capability is becoming essential as wildfire seasons lengthen, ignition points multiply, and landscapes grow drier.
“We’re bringing rotor crews back into the fight,” Kleiman said. “And we’re doing it with precision and purpose.”
Whether over the hills of Los Angeles or the forests of Oregon, one thing is clear: in the battle against wildfire, fire chemistry is becoming just as critical as flight time.