The EPA omitted an emergency trigger from its guidance on groundwater contamination, potentially limiting the agency’s power to intervene in the Pentagon’s efforts to clean up the ubiquitous class of chemicals.

The Environmental Protection Agency’s April 25 draft interim guidance for groundwater that contains the chemicals known as PFOA and PFOS recommends—but doesn’t require—cleanup when the chemicals are found at a concentration of 70 parts per trillion or higher. That recommendation would only apply to groundwater being used for drinking...