Recent court decisions are likely to lead to more stringent permits and emission limits. As reported last month, the D.C. Circuit upheld EPA's greenhouse gas permitting rules, clarifying that states and large emitters of greenhouse gases will now need to consider these emissions and requirements to control them in Clean Air Act permitting decisions. Recent circuit court decisions highlight additional difficulties that emission sources may face when they seek permits. Businesses need to be aware of these issues as they consider permit strategies for possible changes to their facilities.