A plane drops fire retardant in the Angeles National Forest in 2009. (Al Seib / Los Angeles Times )
The U.S. Forest Service is weighing tighter restrictions on aerial fire retardant drops as part of a long-running legal battle over the environmental effects of pouring millions of gallons of the chemical mixture on Western wildlands every year.
Retardant use has soared in recent decades as wildfires have grown larger and more houses have been built on the wildland edge. Nationally, federal and state agencies apply an average of more than 28 million gallons a year, the vast majority of it in the West and much of that in California.
Nearly a third of the retardant used by the Forest Service in the last decade has been in California, where urban development abuts fire-prone wildlands and weather and terrain regularly produce monster blazes.
The proposed limits, outlined in a recently released environmental document, are not expected to cut overall usage. Rather, they are intended to reduce drops on and near waterways, where they can kill fish, and to slightly expand the acreage that is off limits to retardant releases for ecological reasons.
The draft guidelines follow two court decisions that forced federal agencies to reexamine the environmental effects of retardants and the steps that can be taken to minimize harm to endangered species.
"We made a concerted effort to address [the court's] concerns," said Glen Stein, who oversaw the environmental review.
Forest Service guidelines adopted in 2000 bar retardant drops within 300 feet of a body of water. But there are several exceptions: Pilots can release a load over a stream or lake zone if it's necessary to protect life, property or because of terrain limitations.
The California Department of Forestry and Fire Protection, which annually applies an average of 5 million to 6 million gallons of retardant, roughly twice as much as what the Forest Service drops in the state, also follows the 2000 regulations.
The new guidelines would eliminate all but the exception to protect life. They would also require national forests to map areas where drops are to be avoided to protect habitat for imperiled plants and wildlife. And they would increase monitoring for environmental problems.
The Forest Service is expected to make a final decision on the rules by the end of the year. If adopted they would apply only to national forest lands, but could set a precedent for states and other federal land agencies.
"I think it's hinting a new direction," said Andy Stahl, executive director of Forest Service Employees for Environmental Ethics, the advocacy group that has twice sued the Forest Service over retardant.
First used in the 1950s, wildfire retardants today are a blend of mostly water, fertilizer and additives, such as coloring and anti-corrosives to protect aircraft tanks. The mixture does not extinguish flames, but is employed to slow a fire's progress and give ground crews time to dig lines to contain the blaze.
The swoop of air tankers trailing giant orange retardant plumes against a backdrop of towering flames has become such a staple of media coverage that drops can be more about politics than firefighting.
In the 2008 wildfire series "Big Burn," The Times documented instances in the West when the Forest Service conducted expensive retardant attacks to placate politicians who demanded them even when the winds were too strong or the terrain wrong for them to have an effect. Firefighters call them "CNN" drops.
"Aerial fire retardant gives us a false sense of security," said Stahl, arguing that drops are worthless in the wind-whipped fires that are the most destructive and hardest to contain.
The chief environmental concern is retardant's effects on aquatic life and water quality. When the chemical mixture hits a stream or lake, the ammonia in the retardant can be lethal to fish and other organisms. Although the concentrations quickly fall, retardant can have a lingering effect on water chemistry.
If tankers douse stream banks, the retardant can remain toxic for several weeks, during which time rain can wash it into the water.
The Forest Service says that of more than 170,000 retardant loads dumped on public lands in the last decade, only 34 have affected waterways and just a few have killed fish. But in previous environmental documents, the National Marine Fisheries Service argued that many retardant mishaps go undetected by fire crews too busy battling flames to scour remote streams for belly-up fish.
The fisheries agency concluded in 2008 that retardant use in or near waterways could jeopardize more than two dozen endangered and threatened species of fish, including salmon, trout and sturgeon.