Temporary closure

1. When an underground storage tank system is temporarily closed, owners and operators must continue operation and maintenance of corrosion protection in accordance with section 33.1-24-08-21, and any release detection in accordance with sections 33.1-24-08-30 through 33.1-24-08-35 and sections 33.1-24-08-70 through 33.1-24-08-72. Sections 33.1-24-08-40 through 33.1-24-08-43 and sections 33.1-24-08-50 through 33.1-24-08-57 must be complied with if a release is suspected or confirmed. However, release detection and release detection operation and maintenance testing and inspections in sections 33.1-24-08-20 through 33.1-24-08-26 and sections 33.1-24-08-30 through 33.1-24-08-35 are not required as long as the underground storage tank system is empty. The underground storage tank system is empty when all materials have been removed using commonly employed practices so that no more than two and five-tenths centimeters [1 inch] of residue, or three-tenths of one percent by weight of the total capacity of the underground storage tank system, remain in the system. In addition, spill and overfill operation and maintenance testing and inspections in sections 33.1-24-08-20 through 33.1-24-08-26 are not required. 2. When an underground storage tank system is temporarily closed for three months or more, owners and operators must also comply with the following requirements: a. Leave vent lines open and functioning; and b. Cap and secure all other lines, pumps, manways, and ancillary equipment. 3. When an underground storage tank system is temporarily closed for more than twelve months, owners and operators must permanently close the underground storage tank system if it does not meet either performance standards in section 33.1-24-08-10 for new underground storage tank systems or the upgrading requirements in section 33.1-24-08-11, except that the spill and overfill equipment requirements do not have to be met. Owners and operators must permanently close the substandard underground storage tank systems at the end of this twelve-month period in accordance with sections 33.1-24-08-61 through 33.1-24-08-64, unless the department provides an extension of the twelve-month temporary closure period. Owners and operators must complete a site assessment in accordance with section 33.1-24-08-62 before such an extension can be applied for.