Do they really need to conduct a study to determine that spewing black smoke into the air hurts human beings? The Coal lobby must love Trump. Glad millennials won't work for Coal or Oil.
If an administration believes a study's findings would be detrimental to a group it wishes to protect, it might choose to terminate the study before it gets published.
Here's a brief legal article on the subject: https://www.pbwt.com/content/uploads/2015/07/Admission-of-Go...