(a) All components of any new or existing underground storage tank (UST) system subject to the provisions of this subchapter shall be designed, installed, maintained, and operated in a manner that will prevent releases of regulated substances due to structural failure or corrosion.     
      (b) Compatibility.      
        (1) Owners and operators must use a UST system made of or lined with materials that are compatible with the substance stored in the UST system.       
        (2) Biofuels.                  (A) Owners and operators must notify the executive director at least 30 days prior to switching to a regulated substance containing greater than 10% ethanol or greater than 20% biodiesel in accordance with §334.6(b)(1) of this title (relating to Construction Notification for Underground Storage Tanks (USTs) and UST Systems). In addition, owners and operators with UST systems storing these regulated substances must meet one of the following:                      (i) demonstrate compatibility of the UST system (including the tank, piping, containment sumps, pumping equipment, release detection equipment, spill equipment, and overfill equipment). Owners and operators may demonstrate compatibility of the UST system by using one of the following options:                          (I) certification or listing of UST system equipment or components by a nationally recognized, independent testing laboratory for use with the regulated substance stored (such as American Petroleum Institute Recommended Practice 1626, "Storing and Handling Ethanol and Gasoline-Ethanol Blends at Distribution Terminals and Filling Stations."); or                           (II) for equipment or component manufacturer approval, the manufacturer's approval must be in writing, indicate an affirmative statement of compatibility, specify the range of biofuel blends the equipment or component is compatible with, and be from the equipment or component manufacturer; or                         (ii) use another option determined by the executive director to be no less protective of human health and the environment than the options listed in this subsection.                     (B) Owners and operators must maintain records in accordance with §334.10(b) of this title (relating to Reporting and Recordkeeping) documenting compliance with subparagraph (A)(i) of this paragraph for as long as the UST system is used to store the regulated substance.         
      (c) The owners and operators of UST systems subject to the provisions of this subchapter and those persons and/or business entities who engage in, perform, or supervise the installation, repair, or removal of UST systems shall be responsible for ensuring that those UST systems are designed, installed, repaired, removed, and operated in accordance with the provisions of this subchapter, as provided under §334.12(b) of this title (relating to Other General Provisions) and under the provisions of Chapter 70 of this title (relating to Enforcement).     
      (d) When provisions of this subchapter require compliance with a specific code or standard of practice developed by a nationally recognized association or independent testing laboratory, the most recent version of the referenced code in effect at the time of the regulated UST activity shall be applicable.     
      (e) Compliance with the provisions of this subchapter shall not relieve an owner or operator of a UST system from compliance with other applicable regulations legally developed by other governmental entities. This requirement is more fully discussed in §334.12(a) of this title.     
      (f) Unless otherwise stated in a variance approved by the agency in accordance with §334.43 of this title (relating to Variances and Alternative Procedures), the requirements of this subchapter shall take precedence if and when such requirements are determined to be in conflict with any provisions contained in the following:      
        (1) any code or standard of practice developed by a nationally recognized association or independent testing laboratory; and       
        (2) the manufacturer's specifications and instructions for installation and operation of UST equipment.       
      (g) Any underground component of a UST system installed on or after September 29, 1989, shall be properly protected from corrosion by one or more of the allowable methods in §334.49(b) of this title (relating to Corrosion Protection).     
      (h) Any new tank or piping or dispenser installed as part of a UST system on or after January 1, 2009, shall incorporate secondary containment meeting the applicable requirements of §334.45(d) of this title (relating to Technical Standards for New Underground Storage Tank Systems).     
      (i) Any sumps (including dispenser sumps) or manways installed prior to January 1, 2009, which are utilized as an integral part of a UST release detection system to monitor the interstitial space of a secondarily contained piping system, and any spill containment equipment installed at any time, which are associated with a UST system must be inspected at least once every 60 days to assure that their sides, bottoms, and any penetration points are maintained liquid tight. Any liquid or debris found in them during that inspection or an agency or agency-authorized inspection must be removed within 96 hours of discovery and properly disposed. This requirement applies through December 31, 2020, after which the requirements in §334.48(h) of this title (relating to General Operating and Management Requirements), shall apply.     
     Source Note:        The provisions of this §334.42 adopted to be effective September 29, 1989, 14 TexReg 4714; amended to be effective June 25, 1990, 15 TexReg 3424; amended to be effective November 8, 1995, 20 TexReg 8800; amended to be effective November 23, 2000, 25 TexReg 11442; amended to be effective October 30, 2008, 33 TexReg 8790; amended to be effective March 17, 2011, 36 TexReg 1675; amended to be effective May 31, 2018, 43 TexReg 3390