Aircraft battling fires raging through the Los Angeles area are dropping more than water: Hundreds of thousands of gallons of hot-pink fire suppressant ahead of the flames in a desperate effort to stop them before they destroy more neighborhoods.

Perimeter Solutions, the company that makes the substance, explains its hot pink hue. As crews battle fires in Los Angeles, the hot pink fire retardant they’ve dropped to stall the flames’ advance has become one of the striking visuals to come out of the disaster.

The devastating wildfires in California continue. In the fight against the flames, the fire department is distributing a pink extinguishing substance by plane over Los Angeles.

As wildfires rage across Southern California, authorities are deploying pink flame retardants in a desperate effort to contain the flames. But what exactly are these chemicals, and what do we know about their effectiveness and environmental impact?