30 Tex. Admin. Code § 112.19
The owner or operator of a source which emits sulfur dioxide (SO[sub]2[/sub]) may petition the Texas Air Control Board for relief from the requirements of § 112.3(a) of this title (relating to Net Ground Level Concentrations), by filing with the executive director an application for an area control plan. An application for an area control plan shall include, but is not limited to, a combination of evidence that best available control technology is being employed at all the affected sources, having due regard for the technical practicability and the economic reasonableness of reducing or eliminating the emissions of SO[sub]2[/sub] from the affected source, and an ambient air sampling system to record SO[sub]2[/sub] levels in the affected area. Any person who files an application for an area control plan shall demonstrate the capability of all sources in the affected area of the state to maintain all promulgated SO[sub]2[/sub] ambient air quality standards.
30 Tex. Admin. Code § 112.19