Imma Perfetto
Cosmos science journalist
Research is to get underway for the first time into the environmental impact of spraying fire fighting chemicals near waterways.
The researcher involved, Dr Chantal Lanctôt, says “surprisingly little” is known about the ecological impact of these chemicals.
Lanctôt has been awarded an Australian Research Council (ARC) Early Career Industry Fellowship to determine the ecological impacts of firefighting chemicals used to control wildfires.
On 6 May the ARC announced 50 new early career research projects to receive a total of $22.5 million (USD$15m) in research funding.
Lanctôt, a Griffith University ecotoxicologist based on the Gold Coast in Queensland, is to receive almost $500,000 (USD$334,000) to provide scientific evidence to manage the safe use of firefighting chemicals around water catchments.
“The project will assess the ecological impact of chemicals used to fight bushfires in Australia – this will include a range of commonly used retardants, water enhancers and foams,” Lanctôt told Cosmos.
“There is currently little information on the ecological impacts of these chemicals.”
Millions of litres of retardant are dumped on fires every year. For example, in November 2019 the NSW Rural Fire Service said its large air tanker, the Boeing 737 “Marie Bashir”, had flown “135 missions and delivered over 1.45m litres of retardant” in its first 3 months.
Elvis, the Erickson air crane, carries almost 10,000l of retardant and can dump 95,000l an hour. The retardant is mixed with water.
What are firefighting chemicals?
Firefighting chemicals (FFCs) are typically deployed by aircraft or ground crews to suppress and slow the spread or intensity of fires.
“There are currently around 14 fire retardants, 16 Class A foams and 11 water enhancer formulations approved for bushfire management in Australia, with different uses, applications, ingredients, and potential environmental impacts,” says Lanctôt.
“New formulations are also continuously entering the market.”
Class A foams contain surfactants, solvents and other chemicals. They lower the surface tension of water, which helps with the wetting and saturation of Class A materials such as wood, paper, brush and vegetation.
Retardants are chemicals that slow the spread or intensity of a fire. According to Lanctôt, they are commonly made up of ammonium salts of sulphate and/or phosphates, thickeners, corrosion inhibitors, performance additives and dyes.
“For example, the PHOS-CHEK® LC95W formulation we investigated in our recent studies contains [more than] 85% ammonium polyphosphate, [less than] 5% attapulgus clay and [less than] 8% performance additives.”
In April 2023, Cosmos reported on 1 of the studies in the journal Aquatic Toxicology, which found that commonly used FFCs, PHOS-CHEK, LC95W and BLAZETAMER380, can kill frogs or severely delay tadpoles’ growth and development.
BLAZETAMER380 is polymer-based water enhancer, which consist of polymers that absorb large volumes of water. Water enhancers can be applied directly to fire or used to coat vegetation and do not evaporate readily.
The ecological impacts of FFCs are largely unknown
According to Lanctôt, climate-driven fires are becoming more frequent and severe, leading to a widespread increase in the use of firefighting chemicals (FFCs) to protect lives and property.
Working in partnership with government agencies and water utilities, her research will investigate the fate, persistence, and aquatic toxicity of these FFCs to assess their risk to aquatic ecosystems.
The outcomes of the project aim to “inform risk-based management strategies and practices for FFC deployment around water catchments” and “deliver direct environmental benefits by offering a roadmap for responsible FFC use that will guide positive changes in policy and inform the development of greener alternatives”.
Impact on humans
The NSW Department of Health says fire retardants are of “low toxicity”.
It says testing shows these chemicals can produce minor irritant effects before they are mixed with water.
“The concentrated powder may cause minor respiratory irritation to workers who are handling it. Gels can irritate eyes, airways and the skin. Workers are required to wear gloves, goggles and dust masks when handling the powder.
“Risk assessments carried out in the United States and in Victoria demonstrated that the risk of health effects was very low, even to people who are accidentally exposed to the fire retardants during their application.
“The health risk from drinking rain water contaminated with fire retardants is also low, but the water may taste and smell unpleasant and consumption should be avoided.”
