One chain of emails show that American Fuel & Petrochemical Manufacturers (AFPM), a lobby group for oil and gas, coordinated with Pruitt in 2013 to oppose the Renewable Fuel Standard Program and ozone limits. AFPM pursued its own case against the regulations, but later that year, Pruitt also filed a case suing the EPA over the same thing and used similar language to that in the emails.
This worries many Democrats and environmentalists because close ties with oil can often equal a disregard for the well-being of the environment. Republicans, on the other hand, believe that these ties with oil and gas will ensure that the government won’t overreach into those industries. You can find the emails on the Center for Media and Democracy’s website.