An environmental advocacy group argues that the aerial fire retardant used to combat wildfires is leeching into waterways and causing environmental hazards, such as killing endangered fish and creating toxic algae blooms. But fire officials argue that the retardant is critical to their efforts in containing fires.

We speak with Andy Stahl, executive director of the Forest Service Employees for Environmental Ethics, the group bringing the lawsuit.

This article was originally published on WBUR.org.

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