A new legal petition filed by more than 170 top environmental groups demands that the Environmental Protection Agency (EPA) begin monitoring for microplastics in drinking water, an essential first step to reining in pollution viewed as one of the nation’s most pressing public health threats. The scale of microplastic water pollution, the extent to which the substance is lodged throughout human bodies, and the many health implications have come into sharp focus in recent years, but the EPA still has not taken meaningful action, public health advocates say. The petition pushes the agency to begin monitoring microplastics as an emerging contaminant under the Safe Drinking Water Act in 2026.