Dropping fire retardant solutions from airplanes plays a vital role in combating wildfires, but concerns linger regarding their potential environmental consequences, particularly on aquatic ecosystems. These retardants, when deployed, create a reddish or pinkish liquid coating on various surfaces like roads, roofs, and plants. This method, widely adopted since the mid-20th century, assists firefighting teams in controlling fires by cutting off oxygen supply to flames, as explained by Jen Baron, a postdoctoral researcher at the University of British Columbia’s Centre for Wildfire Coexistence.
The B.C. Wildfire Service has been using Phos-Chek LC-95A, a commonly used retardant manufactured by Perimeter Solutions, a global firefighting product company headquartered in the U.S., since 2009. Its primary component, ammonium polyphosphate, is a typical fertilizer. The retardant’s distinctive red color, aiding visibility for crews, is achieved through additives like iron oxide.
Despite the prevalent use of these retardants, their exact chemical composition remains undisclosed. According to Baron, limited research exists on the environmental impact of retardants, though they are generally believed to be safe for both people and the environment. However, Baron points out the restrictions on their use near water bodies due to potential harm to aquatic life from ammonia and phosphate present in the retardants.
Accidents involving retardants are infrequent but not entirely unheard of, as highlighted by Uldis Silins, a forest hydrology professor at the University of Alberta. In 2020, Silins and his team investigated the long-term effects of retardants following an accidental discharge of Phos-Chek LC-95-A over North Racehorse Creek in southwest Alberta during firefighting operations. The subsequent research revealed phosphorus-enriched sediments downstream, challenging the assumption that retardants dissipate quickly from ecosystems.
With the escalating threat of wildfires due to climate change, Silins predicts a surge in retardant usage, emphasizing the inevitability of accidents. While recognizing the potential risks, experts like Silins and Evelyne Thiffault from Laval University stress the necessity of retardants in safeguarding public safety during wildfire emergencies.
Research on retardants like Phos-Chek remains crucial, considering their proprietary chemical composition and potential environmental impacts. Recent studies have uncovered toxic elements like chromium, arsenic, and lead in uncolored versions of Phos-Chek LC-95A, prompting calls for further exploration and the development of eco-friendly alternatives to minimize ecosystem impacts.
Perimeter Solutions, the company manufacturing Phos-Chek, asserts the rigorous testing of its product and emphasizes adherence to established guidelines to prevent adverse effects, including avoiding drops over water bodies. As efforts continue to enhance understanding and mitigate the environmental impact of fire retardants, ongoing research and innovation are pivotal in ensuring the safety of both ecosystems and communities.