Concerns for wildlife rise as swaths of BC are spattered red

Monday, July 24, 2017, 5:41 PM - Firefighting efforts in British Columbia have been in overdrive most of this month, with more than 4,000 crew involved in combating the more than 150 fires currently burning across the province, on land and by air.

With large swaths of the province's forests - and in some cases, towns - now coated with red fire retardant, some concerns are being raised over the impact of air-dropped fire retardant on the environment.

While the main type of retardant used in Canada - PHOS-CHEK - is rated as safe for humans and other mammals, it's a different story for marine life.

The retardant is composed of a blend of water, ammonia salts (the active fire retarding component), a thickening agent (to make spraying easier to direct), and a colouring agent (to help identify treated areas). The B.C. Wildfire service calls the mixture "an essentially water soluble, industrial strength fertiliser with colouring." When fire comes in contact with the salts, the reaction releases water and carbon dioxide, both serving to combat the flames.

According to a CBC News report, the B.C. Wildfire service has already dropped 8 million litres of retardant this year. The yearly average is 9.4 million litres.

A 2014 study published by researchers at the U.S. National Oceanic and Atmospheric Administration (NOAA) found that, in cases where fire retardant products entered the watershed, it led to fish kills. The study, which focused on Chinook salmon, found that the retardant chemicals can not only be toxic to the fish during initial exposure, but can increase later mortality rates as well.

A PHOS-CHEK product sheet does state that, while the retardant has a "relatively low order of acute toxicity [to fish] ... the free ammonia present in all fire retardant solutions can be quite toxic to aquatic life when directly applied."

Since the substance is designed to coat trees and other vegetation, waterways are not the target of drops, but sometimes accidents happen. In 2002, thousands of gallons of retardant were dropped into a river in Oregon, resulting in the immediate death of about 21,000 fish.

Changes in wind and human error can both result in the retardant landing outside of the targeted zone - something that residents of Cache Creek discovered last week when they returned to find their properties covered in dried red goop.

While the substance does break down to become fertiliser, even that can could cause issues with runoff, as fertiliser can feed harmful algal blooms.

The retardant information sheet recommends care be exercised to minimize how much of the substance finds its way into bodies of water, but acknowledges "some contamination may occur" since ponds and other small bodies of water may be hidden by foliage. It also states that, because they are very sensitive to water temperature changes and runoff debris from affected areas, it's not unusual for fish and other aquatic life to be among the victims of large wildfires.

Sources: CBC News | PHOS-CHEK | Live Science | B.C. Wildfire Service | Science Direct | B.C. CDC |

Watch below: How to fight a wildfire