Among his last acts as president, Donald Trump signed an executive order mandating a study of exposure to toxic materials among U.S. military personnel who served at an air base in Uzbekistan from October 1st, 2001, to December 31st, 2005. The Secretary of Defense is to conduct a study on toxic exposures and any subsequent adverse health effects experienced by U.S. troops assigned to the base after a number of toxins and ground contaminants were discovered at the site, and may have a role in elevated levels of cancer and other illness among those who served at the base.