The Environmental Protection Agency’s decision not to include microplastics in its list of regulated chemicals has caused a stir among Democrats and environmental health advocates. 

Several members of Congress demanded earlier this week that the EPA Administrator Lee Zeldin include microplastics on the agency’s Unregulated Contaminant Monitoring Rule 6, or UCMR, which is updated every five years to direct public water systems to monitor contaminants in the water supply.