Context:

Pink fire retardant is being used to curb California wildfires currently, which has environmental concerns.

About Fire Retardant and its Pink Colour

Flame retardants are a mix of chemicals that are applied to materials to prevent the start or slow the growth of fire.

The retardant for wildfire works by spraying ahead of fires to coat vegetation and reduce oxygen, preventing fires from spreading.

Long-term retardants used in wildfire control are typically made up of 85% water, 10% fertilizer (usually ammonium phosphate), and 5% minor ingredients, including:

• Colorant
• Corrosion inhibitors
• Thickener (natural gum and clay)
• Stabilizers
• Bactericides

Colorants are added to make the fire retardants visible, this helps pilots track where previous drops were made.

• It also allows them to aim future drops accurately to connect or reinforce retardant lines.
• Phos-Chek is a popular brand of pink fire retardant used in the U.S., primarily made of ammonium phosphate-based slurry which does not evaporate easily.

Fire retardant contains salts (typically fertilizers) that alter the way wildfires burn, decreasing fire intensity and slowing the advance of the fire, even after the water in the fire retardant has evaporated. 

The water in long-term fire retardants serves primarily to aid in uniform dispersal of the chemical over the target area. 

Concerns Around the Use of Fire Retardants

The use of fire retardant in the US is not new as the data shows that 440 million gallons of retardant were unleashed on federal, state, and private land between 2009 and 2021, which released more than 400 tons of heavy metals into the environment. 

Environmental experts have said that spraying fire retardants using planes is ineffective, expensive and a growing source of pollution for rivers and streams. 

• Because these chemicals do not easily break down, they can remain in the environment and in the body for years. 

Firefighting agencies and manufacturers like Perimeter Solutions defend their use as essential for wildfire control, especially with rising temperatures and increasing wildfire frequency.

The University of Southern California (USC) 2024 study found that Phos-Chek contains toxic metals like chromium and cadmium, which can be harmful to human health and the environment.

• These chemicals can pollute rivers and streams, threatening aquatic life.