The hundreds of thousands of gallons of red slurry that air tankers are dropping on Colorado forests to shield mountain houses from wildfires has a downside: It is toxic. Laced with ammonia and nitrates, it has the potential to kill fish and taint water supplies.
Federal authorities say they’re implementing new rules prohibiting application of fire-retardant chemicals within 600 feet of waterways. Air tanker pilots and crew commanders now are required to carry maps that identify sensitive terrain — such as areas where greenback cutthroat trout and Pawnee montane skipper butterflies are monitored as sentinel species.