In only 20 seconds, these planes can drop massive tankfuls of bright pink fire retardant from above the blazing flames. They are widely regarded as essential in the fight against wildfires.
However, new studies have revealed that the millions of gallons of retardant that are sprayed on the landscape annually to control wildfires have a hazardous impact since they include chemicals and heavy metals that are bad for the ecosystem and human health.
The toxicity poses a serious problem. When it comes to controlling fatal fires, these tankers and their payload are an effective weapon. However, firefighters are using them more frequently and releasing more hazardous chemicals into the environment as wildfires get worse and occur more frequently in the age of climate change.
The efficacy and possible risks of the retardants have been questioned by several environmental organizations. Since fire retardant is one of several firefighting techniques used in a large fire, its effectiveness has proven difficult to gauge. It’s hard to give credit once the fire has been out.
In recent years, wildfires have become more frequent and severe, especially in the western United States. Researchers have also shown that in recent decades, flames have spread more quickly over the area.
Additionally, exposure to wildfire smoke can have long-term health impacts since it can enter the heart and lungs and cause illness.
Daniel McCurry, an assistant professor of civil and environmental engineering at the University of Southern California, who oversaw the recent study on fire retardants’ heavy-metal content, said that these health and environmental costs are increased by fire retardants because they offer “a really, really thorny trade-off.”
Tens of thousands of people have been affected by the flames in Southern California, and the USFS announced Thursday that it was deploying 20 water-dropping helicopters and nine big planes that spray retardants. They are also using a number of “water scooper” amphibious planes, which can fill their tanks by skimming the sea or other body of water.
According to Stanton Florea, a spokesman for the National Interagency Fire Center in Boise, Idaho, which organizes national wildland firefighting efforts throughout the West, two sizable DC-10 aircraft, known as “Very Large Airtankers,” that can transport up to 9,400 gallons of retardant are also expected to join the fleet soon.
According to Mr. Florea, the retardants, which are sprayed before the fire, cover the grass and stop oxygen from causing it to burn. (To help firefighters notice the retardant against the landscape, red dye is applied.) Additionally, the retardant “lasts longer” and is usually composed of salts like ammonium polyphosphate. Unlike dripping water, it doesn’t evaporate,” he added.
However, the latest study by Dr. McCurry and his colleagues discovered that a typical type of retardant used by firemen included at least four distinct types of heavy metals, including chromium and cadmium, in excess of California’s hazardous waste regulations.
Between 2009 and 2021, almost 440 million gallons of retardant were sprayed to federal, state, and private lands, according to official statistics. Based on that amount, the researchers calculated that fire suppression contributed to the release of almost 400 tons of heavy metals into the environment between 2009 and 2021, with Southern California accounting for a third of that total.
Perimeter Solutions, the maker of the retardant, and the federal government have both contested that findings, claiming the researchers had tested an alternative retardant formulation. Retardants used for aerial firefighting have passed “extensive testing to confirm they meet strict standards for aquatic and mammalian safety,” according to Perimeter spokesperson Dan Green.
Nevertheless, the results contribute to the understanding of why heavy metal concentrations in rivers and streams may increase hundreds of times following wildfires. Additionally, the Forest Service has established buffer zones around lakes and rivers in response to increased scrutiny of fire suppressants, despite the fact that its own data indicates that the retardant still unintentionally wanders into those bodies of water.
