Some of USA’s largest refineries are in a state of uncertainty on news that the US Environmental Protection Agency has officially overturned a 16-year-old Texas air permitting program that is said to violates the Clean Air Act. The EPA's move is with regard to Texas' flexible permits, which set a general limit on how much air pollutants an entire facility can release. The federal Clean Air Act requires state-issued permits to set limits on each of the dozens of individual production units inside a plant. The EPA says Texas' system masks pollution and makes it impossible to regulate emissions and protect public health. Texas has been issuing the permits since 1994 even though it never received the required federal approval. Atleast 5 years ago, the EPA clarified that it believes the permits violated federal air laws, warning Texas and the refinery and petrochemical industry it would take action. The industry, uncomfortable with the uncertainty, sued the EPA in 2008, demanding the agency take action on this and several other programs that remained in limbo.