In August 2001, Chris Fisher, an anadromous fisheries biologist for the Confederated Tribes of the Colville Reservation, set out to inspect Omak Creek in eastern Washington in response to reports that the “river was running red.”

His first encounter with the creek revealed fifty to sixty dead summer steelhead and rainbow trout swirling in the center of a pool that formed at the base of a waterfall. He walked five or six miles along the creek, noting dead fish in pools and piled up behind fallen tree limbs. The stream was pink, the rocks and foliage coated with thick red fire retardant that had been accidentally dropped on the creek four days earlier in an effort to control the Saint Mary’s Fire, which burned approximately 8,000 acres in the Omak Creek watershed.

“A multitude of species in all life stages were killed,” he says. “It was morbid.”

Fire retardant is just one of the many weapons in the firefighting arsenal, but it is one of the more spectacular ones. Air tankers with cargo capacity of 2,000 to 3,000 gallons of retardant dropped approximately 20,000 loads to slow the advance of fire in 2002. The entire fire aviation program, which involves multiple agencies, has expenditures in excess of $250 million a year, at least 15 percent of the federal wildfire budget. Several years ago, the cost of fire retardant alone was estimated at $95 million.

When used correctly, retardant can be effective. Retardants are composed primarily of common agricultural fertilizers, such as ammonium sulfate and diammonium phosphate. Unlike water, retardant is dropped ahead of flames to slow them and give ground support forces time to build fire lines. But there is little disagreement that when retardant comes in contact with aquatic areas, the resulting environmental damage can be severe, causing immediate fish kills and polluting the waterways.

Some retardants contain sodium ferrocyanide, an agent that is used as an anticorrosive ingredient. Sodium ferrocyanide became a lightning rod in March 2000, when the U.S. Forest Service banned the use of retardants that contained it. Of the two companies that provide retardant to the government, Fire-Trol and Astaris, only Fire-Trol contains sodium ferrocyanide. The company vigorously protested the ban, which was lifted a month later. The Forest Service agreed to discontinue the use of retardant with sodium ferrocyanide by 2004.

Rob Crouch, spokesman for Phoenix-based Fire-Trol, says the danger of fire retardant comes not from the sodium ferrocyanide, but from the drop on aquatic systems.

“Taking the sodium ferrocyanide out won’t change a thing,” he says. “Every retardant causes damage when dropped into waterways.”

In a way, he’s right. Sodium ferrocyanide converts to free cyanide, its toxic form, only when it is exposed to ultraviolet rays through water, says Susan Finger, a toxicologist at the U.S. Geological Survey. Free cyanide is immediately and acutely toxic to fish, but without the presence of sunlight and water, conversion won’t occur and sodium ferrocyanide will cause no harm. After the conversion, it dissipates almost immediately.

The other retardant ingredients have more staying power. At Omak Creek, Jeff Fisher, a biologist and toxicologist working for a private contractor, says water samples showed only trace amounts of cyanide, but ammonia levels were several orders of magnitude higher than what is tolerable to fish. He speculates that it was the ammonia that caused the large-scale mortality rate, but acknowledges that it is hard to know for sure.

Whether or not retardant drops are lethal depends on several factors. The amount of the load, the size of the stream and the volume of the flow will affect concentration and dilution levels. Most forest fires occur during hot summer months, when the potential for chemicals to dilute rapidly is diminished due to low stream flows.

Forest Service officials estimate that during the 2002 fire season, one of the worst the West has seen, 33.6 million gallons of retardant were pumped from fixed-wing stations, and perhaps half again that much from temporary portable bases. That’s a lot of fertilizer to be dumped on the ground or, in some cases, in the water.

The Forest Service requires a 300-yard buffer zone around waterways, but accidents do happen. A report from the National Interagency Fire Center in Boise documents six cases of retardant hitting waterways since 2001, but because there is no standardized method for reporting retardant drops into streams and because occurrences are often dealt with locally, it is difficult to gather information on a national level.

But avoiding waterways doesn’t address the use of retardant in its entirety. Retardant chemicals can enter the waterways postfire through run-off. The amount of time the chemicals remain toxic following a fire depends on soil conditions, weather and aquatic dilution. Excessive fertilizer dropped on sensitive ecological areas can kill plants or cause temporary burn.

And let’s not forget the human cost. After air tanker crashes resulted in the deaths of five airmen last year, Forest Service Chief Dale Bosworth convened a blue ribbon panel on aerial safety. Their report, delivered in December 2002, stated, “Millions of dollars are spent each year to keep the approximately 40 to 46 large air tankers on-contract and available for firefighting. However, there are few checks and balances to ensure that the aircraft are airworthy and safe to fly throughout a fire season.” The panel determined that the fatal air tanker crashes were predictable given the age of the fleet and the difficulty of maintaining it. Following the crashes, the Forest Service grounded about a quarter of the fleet pending safety inspections and has since instituted a rigorous inspection and maintenance program.

Is the use of fire retardant worth the high cost? Tim Ingalsbee, director of the Western Fire Ecology Center for the American Lands Alliance, says there is a narrow range of conditions under which retardant is effective. “There are some benefits, but you have to have the right time, place and condition for retardant use. And that’s not happening. It’s just wholesale toxic chemical dumping on national forests.”

At Omak Creek, an estimated 10,040 trout were killed in a 5.5-mile stretch. The incident report states that “it is suspected that most, if not all, natural reproduction of summer steelhead in Omak Creek were killed from this retardant drop.”

Jeff Fisher, the biologist who consulted on the Omak Creek spill, is not sure that the use of fire retardant was warranted for the Saint Mary’s Fire.

“It was a low-intensity burn with not a lot of property at risk,” he says. “They probably didn’t need to use anything. They just direct-hit this creek.”