On January 5, 2021, EPA finalized a rule to limit the use of scientific studies for which underlying data is not publicly available. Commenters have warned that researchers are often unable to share study participants' confidential information, and that the EPA's rule will hamstring the agency from relying on important public health studies. The final rule applies to scientific data that the agency uses in crafting regulations as well as all "influential scientific information" at the agency, a broad term that could apply to informal guidance or other agency actions.