(a) Except as provided in subsection (b) of this section, the following aboveground storage tanks (ASTs) are excluded from regulation under this subchapter:      
        (1) any tank with a capacity of 1,100 gallons or less;       
        (2)  any emergency spill protection or emergency overflow containment tank, including any sump or secondary containment system, which is used solely for the temporary storage or containment of petroleum products resulting from a leak, spill, overfill, or other unplanned release of petroleum products from any source, and where the petroleum products are routinely removed within 48 hours of the discovery of the release, provided that this tank must be inspected for a release no less than once every 30 days;       
        (3) any tank that contains petroleum products at such dilute concentrations that:                  (A) the mixture is not capable of being used as a fuel for the propulsion of a motor vehicle or aircraft; and                   (B) any release would not pose any significant threat to human health and safety or the environment;         
        (4) a transformer or other electrical equipment that is used in the transmission of electricity.       
      (b) Regardless of the exemptions in subsection (a) of this section, any AST containing petroleum products located at a retail service station is subject to the construction notification requirements of §334.126 of this title (relating to Installation Notification for Aboveground Storage Tanks (ASTs)).     
      (c) Upon request by the agency, the owner and operator of a tank claimed to be excluded under this section must provide appropriate documentation or other information in a timely manner to support that claim.     
     Source Note:        The provisions of this §334.124 adopted to be effective June 25, 1990, 15 TexReg 3424; amended to be effective November 23, 2000, 25 TexReg 11442; amended to be effective May 31, 2018, 43 TexReg 3390