Is the pink fire retardant dropped by planes on California fires safe?

From above the raging flames, these aircraft can release massive amounts of bright pink flame retardants in just 20 seconds. They have long been considered vital in the battle against wildfires.

but Emerging research It has shown that millions of gallons of retardants sprayed on landscapes to tame wildfires each year carry a toxic burden, because they contain heavy metals and other chemicals that harm human health and the environment.

Toxicity presents a stark dilemma. These tankers and their cargo are a powerful tool for taming deadly fires. However, as wildfires become more intense and more frequent in the era of climate change, firefighters are using them more often, and in the process releasing more harmful chemicals into the environment.

Some environmental groups have questioned the effectiveness of inhibitors and the potential for harm. The effectiveness of fire retardants has been difficult to measure, because it is one of a wide range of firefighting methods used in a large fire. After the fire is extinguished, it is difficult to determine credit.

The frequency and severity of wildfires has increased in recent years, especially in the western United States. Scientists have also found that fires occur throughout the region It’s moving faster In recent decades.

There are also the long-term health effects of exposure to wildfire smoke, which can penetrate the lungs and heart and cause illness. A Recent global survey Of the health effects of air pollution caused by wildfires, exposure to wildfire smoke in the United States has increased by 77 percent since 2002. Globally, wildfire smoke has been estimated To be responsible For up to 675,000 premature deaths Every year.

Fire retardants add to those health and environmental burdens because they represent a “really thorny trade-off,” said Daniel Macari, an assistant professor of civil and environmental engineering at the University of Southern California, who led recent research on heavy-duty fire retardants. – Mineral content.

The US Forest Service said Thursday that nine large retardant-spraying aircraft, in addition to 20 water-dropping helicopters, have been deployed to fight the Southern California fires, which have displaced tens of thousands of people. Many “water scoop” amphibious aircraft are also used, capable of skimming the surface of the sea or other body of water to fill their tanks.

Two large DC-10 aircraft, dubbed “Very Large Airtankers” capable of delivering up to 9,400 gallons of retardant, are scheduled to fly, said Stanton Florea, spokesman for the National Interagency Fire Center in Boise, Idaho. You’ll be joining the fleet soon. Which coordinates national efforts to combat wildland fires throughout the West.

These retardants, which are sprayed before a fire, cover the plants and prevent oxygen from burning them, Mr. Florea said. (A red dye is added so firefighters can see the retardant on the landscape.) The retardant, usually made from salts such as ammonium polyphosphate, “lasts longer.” “It doesn’t evaporate, like water droplets,” he said.

However, new research by Dr. McCurry and colleagues found that at least four different types of heavy metals, including chromium and cadmium, that were present in a common type of retardant used by firefighters, exceeded California’s requirements for hazardous waste.

More than 440 million gallons of retardants were used on federal, state and private lands between 2009 and 2021, federal data show. Using that number, researchers estimated that between 2009 and 2021, more than 400 tons of heavy metals were released onto federal lands. environment of fire suppression, one-third that of Southern California.

Both the federal government and the manufacturer of the butt, Perimeter Solutions, have disputed this analysis, saying the researchers evaluated a different version of the butt. Perimeter spokesman Dan Green said retardants used in aerial firefighting have passed “extensive testing to ensure they meet stringent aquatic and mammalian safety standards.”

However, the findings help explain why heavy metal concentrations tend to, and sometimes do, rise in rivers and streams after wildfires Hundreds of times. With increasing scrutiny of fire suppression methods, the Forest Service has created buffer zones surrounding lakes and rivers, although Its data It appears that inhibitors are still inadvertently drifting into those waters.

In 2022, the nonprofit Forest Service Employees for Environmental Ethics sued the government in federal court in Montana, demanding that the Forest Service obtain a permit under the Clean Water Act to cover accidental spraying into waterways.

The judge ruled that the agency did need to obtain a permit. But it allowed the use of breeches to continue protecting life and property.