Congressional Democrats yesterday expressed outrage that the Department of Health and Human Services still hasn’t published a toxicology study that a White House official earlier this year described as a “potential public relations nightmare.”

The lawmakers are demanding that the study be released immediately and that an oversight hearing be held.

The study of four types of stain- and water-resistant chemicals is being conducted by HHS’s Agency for Toxic Substances and Disease Registry, or ATSDR.

An unnamed member of the White House’s intergovernmental affairs team warned that the draft toxicology profile of the per- and polyfluoroalkyl substances, or PFAS, “has some very, very low ‘Minimal Risk Level’ (MRL) numbers,” the lowest of which is 12 parts per trillion in drinking water — over 80 percent below the current maximum safe level EPA has advised for two types of PFAS.