567—135.15(455B) Out-of-service UST systems, temporary closure, and permanent closure.
	135.15(1) Out-of-service UST systems and temporary closure.
	a. 	UST systems not meeting either the performance standards in subrule 135.3(1) for new UST systems or the upgrading requirements in subrule 135.3(2) by December 22, 1998, must be permanently closed according to subrule 135.15(2). The tanks cannot be brought back into use.
	b. 	When a UST system in compliance with new tank standards is out of service for less than three months, owners and operators must:
	(1)	Continue operation and maintenance of corrosion protection in accordance with subrule 135.4(2);
	(2)	Continue operation and maintenance of any release detection in accordance with rule 567—135.5(455B) unless the system is empty. The UST system is empty when all materials have been removed using commonly employed practices. No more than 2.5 centimeters (1 inch) of residue, or 0.3 percent by weight of the total capacity of the UST system, may remain in the system;
	(3)	Comply with rules 567—135.6(455B) to 567—135.12(455B) if a release is suspected or confirmed;
	(4)	Maintain financial responsibility (e.g., insurance) in accordance with 567—Chapter 136. If at any time financial responsibility coverage is or will be terminated, a site check for contamination must be completed before coverage is terminated. A site check must use the closure-in-place sampling procedures in paragraphs 135.15(3)“b” and “d” or the Tier 1 site assessment in rule 567—135.9(455B). If the tanks are located in a contaminated area with active monitoring and remediation, the tank owner may request the department waive the site check providing justification.
	(5)	Continue to pay the tank management fee as required in subrule 135.3(5).
	(6)	Continue to have compliance inspections conducted as required in rule 567—135.20(455B).
	c. 	When a UST system is out of service for three months or more, an owner must submit a notification of temporary closure form to the department. Owners and operators must complete the requirements in paragraph 135.15(1)“b” for temporary closure and certify the following:
	(1)	The UST system is empty of all regulated substances (e.g., receipt of product removal).
	(2)	Vent lines are open and functioning.
	(3)	All other piping, pumps, accesses, and ancillary equipment are capped and locked.
	(4)	The corrosion protection system is being maintained in accordance with subrule 135.4(2). Include documentation that electricity is being maintained to operate the impressed current cathodic protection system if present.
	(5)	For lined tanks, provide a copy of the last internal inspection.
	(6)	Provide proof of financial responsibility (e.g., insurance) according to 567—Chapter 136.
	d. 	When a tank system is temporarily closed for more than 12 months, the owner must remain in compliance with the department’s temporary closure requirements in paragraph 135.15(1)“c.” The department may provide an extension to the 12-month temporary closure period. Owners and operators must complete a site check in accordance with paragraph 135.6(3)“b” before such an extension can be applied for.
	e. 	If a tank system is temporarily closed for more than 12 months, but the tank system has not been temporarily closed according to the requirements of paragraph 135.15(1)“c,” or the owner or operator has failed to maintain out-of-service requirements in paragraph 135.15(1)“b,” the UST system must be permanently closed in accordance with subrule 135.15(2).
	f. 	Prior to returning a temporarily closed tank back into service, the owner or operator must complete and submit the department’s return-to-service form signed by a licensed installer and provide the following documentation. The tank system cannot be operated or receive fuel until current tank tags have been issued.
	(1)	Documentation that the tanks were temporarily closed in accordance with subrule 135.15(1).
	(2)	Where applicable, documentation that corrosion protection has been maintained continuously in accordance with subrule 135.4(2). The owner or operator must provide an inspection log of the cathodic protection system and the inspection report of the cathodic protection system completed by an Iowa-licensed corrosion tester.
	(3)	For lined tanks, provide a lining and tank integrity inspection report.
	(4)	Results of precision tightness tests (0.1 gph) conducted on tanks in accordance with rule 567—135.5(455B).
	(5)	Results of precision tightness tests (0.1 gph) conducted on lines in accordance with rule 567—135.5(455B). This includes piping used for remote fill.
	(6)	Function test (3.0 gph) results of mechanical or electronic leak detectors conducted in accordance with rule 567—135.5(455B).
Note: Function tests are not required on confirmed “safe suction” dispensing lines.
	(7)	Tank and piping leak detection is operational and in good condition.
	(8)	Secondary containment is installed where necessary in accordance with subrule 135.3(9).
	(9)	Spill containment, overfill prevention and all containment sumps are in good condition and operating in accordance with subrule 135.4(1). Tightness tests conducted within the last 12 months must be provided for secondary containment of tanks, piping, sumps, under dispenser containment and spill containment.
	(10)	Copy of the financial responsibility (e.g., UST insurance) mechanism in accordance with 567—Chapter 136.
	(11)	Certification from an Iowa-licensed installer that the UST system and equipment are installed correctly, are in good operable condition and meet all regulatory requirements for startup and operation.
	(12)	Copies of Class A and Class B operator training certificates.
	(13)	Change of ownership form (if the UST facility was sold).
	135.15(2) Permanent closure and changes-in-service. Permanent closure of an underground storage tank system must be conducted by an Iowa-licensed tank remover. Closure sampling must be conducted by or under the supervision of an Iowa-certified groundwater professional.
	a. 	At least 30 days before beginning either permanent closure or a change-in-service under paragraphs “b” and “c” below, owners and operators must notify the department of their intent to permanently close or make the change-in-service. An owner or operator must seek prior approval to permanently close a tank in a time frame shorter than the 30-day notice. The required assessment of the excavation zone under 135.15(3) must be performed after notifying the department but before completion of the permanent closure or a change-in-service.
	b. 	To permanently close a tank or piping, owners and operators must empty and clean them by removing all liquids and accumulated sludge. All tanks taken out of service permanently must also be removed from the ground, filled with an inert solid material, or closed in place by a method approved by the department. Piping must be removed from the ground or have the ends plugged with an inert solid material.
When permanently closing a tank by filling with inert solid material, the tank may not be filled until a closure report is approved by the department. The tank must be filled within 30 days after department approval. The owner and operator must notify the department within 15 days after filling the tank with inert solid material.
	c. 	Continued use of a UST system to store a nonregulated substance is considered a change-in-service. Before a change-in-service, owners and operators must empty and clean the tank by removing all liquid and accumulated sludge and conduct a site assessment in accordance with 135.15(3).
	d. 	Permanent closure procedures must be followed in the replacement of tanks or piping. Notification must be made using DNR Form 542-1308, “Notification of Tank Closure or Change-in-Service.” The form must include the date scheduled for the closure. Oral confirmation of the closure date must be given to the DNR field office 24 hours prior to the actual closure. The required assessment of the excavation zone under subrule 135.15(3) must be performed after notifying the department but before completion of the permanent closure or change-in-service.
Note: The following cleaning and closure procedures may be used to comply with subrule 135.15(2):
	●	American Petroleum Institute Recommended Practice RP 1604, “Closure of Underground Petroleum Storage Tanks”;
	●	American Petroleum Institute Standard 2015, “Safe Entry and Cleaning of Petroleum Storage Tanks, Planning and Managing Tank Entry From Decommissioning Through Recommissioning”;
	●	American Petroleum Institute Recommended Practice 2016, “Guidelines and Procedures for Entering and Cleaning Petroleum Storage Tanks”;
	●	American Petroleum Institute Recommended Practice RP 1631, “Interior Lining and Periodic Inspection of Underground Storage Tanks,” may be used as guidance for compliance with this subrule;
	●	National Fire Protection Association Standard 326, “Standard for the Safeguarding of Tanks and Containers for Entry, Cleaning, or Repair”; and
	●	National Institute for Occupational Safety and Health Publication 80-106, “Criteria for a Recommended Standard...Working in Confined Space” may be used as guidance for conducting safe closure procedures at some hazardous substance tanks.
	135.15(3) Assessing the site at closure or change-in-service.
	a. 	Before permanent closure or a change-in-service is completed, owners or operators must measure for the presence of a release where contamination is most likely to be present at the UST site. This soil and groundwater closure investigation must be conducted or supervised by a groundwater professional certified under 567—Chapter 134, Part A, unless the department in its discretion grants an exemption and provides direct supervision of the closure investigation. In selecting the sample types, sample locations, and measurement methods, owners and operators must consider the method of closure, the nature of the stored substance, the type of backfill, the depth to groundwater, and other factors appropriate for identifying the presence of a release.
At UST sites with a history of petroleum storage, soil and groundwater samples shall in every case be analyzed for benzene, toluene, ethylbenzene, and xylenes (BTEX) with each compound reported separately in accordance with rule 567—135.16(455B). If there has been a history or suspected history of petroleum storage other than gasoline or gasoline blends (i.e., all grades of diesel fuels, fuel oil, kerosene, oil and mineral spirits), or such storage history is unknown or uncertain, soil and groundwater samples shall also be analyzed for total extractable hydrocarbons in accordance with rule 567—135.16(455B).
All such samples shall be collected separately and shipped to a laboratory certified under 567—Chapter 83 within 72 hours of collection. Samples shall be refrigerated and protected from freezing during shipment to the laboratory.
When a UST is removed from an area of confirmed contamination, the department may waive closure sampling if written documentation is submitted with the closure notification. Documentation should include laboratory analytical reports and a site map showing tank and piping locations along with contamination plume and sampling locations.
	b. 	For all permanent tank and piping closures or changes-in-service, at least one water sample must be taken from the first saturated groundwater zone via a developed monitoring well except as provided in paragraph 135.15(3)“g.”The well must be located downgradient from and as close as possible to the UST system but no farther away than 20 feet from system components. At some tank and piping closures, a minimum of one monitoring well may not be sufficient to represent a release where it is most likely to be present. An additional groundwater monitoring well or wells may be necessary.
If, however, the first saturated groundwater zone is not encountered within 10 feet below the lowest elevation of the tank excavation, the requirement for groundwater sampling shall not apply unless:
	(1)	Sands or highly permeable soils are encountered within 10 feet below the lowest level of the tank excavation which together with the underlying geology would, in the judgment of the department, pose the reasonable possibility that contamination may have reached groundwaters deeper than 10 feet below the lowest level of the tank excavation. The method of determining highly permeable soil is found in the departmental guidance documents entitled “Underground Storage Tank Closure Procedures for Tank and Piping Removal” and “Underground Storage Tank Closure for Filling in Place.”
	(2)	Indications of potential groundwater contamination, including petroleum products in utility lines, petroleum products in private wells, petroleum product vapors in basements or other structures, occur in the area of the tank installation undergoing closure or change-in-service.
	c. 	For permanent closure by tank removal, the departmental guidance document entitled “Underground Storage Tank Closure Guidance” must be followed. The minimum number of soil samples that must be taken depends on the tank size and length of product piping. Samples must be taken at a depth of 1 to 2 feet beneath the tank fill area below the base of the tank along the tank’s centerline. Soil samples must also be taken at least every 10 feet along the product piping at a depth of 1 to 2 feet beneath the piping fill area below the piping, unless alternate sampling is approved by the department.
If sands or other highly permeable soils are encountered, alternative sampling methods may be required.
If contamination is suspected or found in any area within the excavation (i.e., sidewall or bottom), a soil sample must be taken at that location.
The numbers of samples required for tanks are as follows:

Nominal Tank Capacity
(gallons)	Number of
Samples	Location
on Centerline	
1,000 or less	1	center of tank	
1,001 - 8,000	2	1/3 from ends	
8,001 - 30,000	3	5 feet from ends and at center of tank	
30,001 - 40,000	4	5 and 15 feet from ends	
40,001 and more	5	5 and 15 feet from ends and at center of tank	
	d. 	For closing a tank in place by filling with an inert solid material or for a change-in-service, the departmental guidance document entitled “Underground Storage Tank Closure for Filling in Place” must be followed. The minimum number of soil borings required for sampling depends on the size of the tank and the length of the product piping. Soil samples must be taken within 5 feet of the sides and ends of the tank at a depth of 2 to 4 feet below the base of the tank, but outside the backfill material, at equal intervals around the tank. Soil samples must also be taken at least every 10 feet along the product piping at a depth of 1 to 2 feet beneath the piping fill area below the piping, unless alternate sampling is approved by the department. If sands or other highly permeable soils are encountered, alternative sampling methods may be required.
The minimum numbers of soil borings and samples required are as follows:

Nominal Tank Capacity
(gallons)	Number of
Samples	Location
of Samples	
6,000 or less	4	1 each end and each side	
6,001 - 12,000	6	1 each end and 2 each side	
12,001 or more	8	1 each end and 3 each side	
	e. 	A closure report in a format prescribed by the department must be submitted to the department within 45 days of the tank removal or sampling for a closure in place. Refer to the Underground Storage Tank Closure Guidance for reporting format. The tank tags must be returned with the closure report.
	f. 	The requirements of this subrule are satisfied if one of the external release detection methods allowed in 135.5(4)“e” and “f” is operating in accordance with the requirements in 135.5(4) at the time of closure and indicates no release has occurred.
	g. 	If contaminated soils, contaminated groundwater, or free product as a liquid or vapor is discovered during the site assessment or by any other manner, contact the department in accordance with 135.6(1). Normal closure procedures no longer apply. Owners and operators must begin corrective action in accordance with rules 567—135.7(455B) to 567—135.12(455B).
Identification of free product requires immediate response in accordance with 135.7(5). If contamination appears extensive or the groundwater is known to be contaminated, a full assessment of the contamination will be required. When a full assessment is required or anticipated, collection of the required closure samples is not required. If contamination appears limited to soils, overexcavation of the contaminated soils in accordance with 135.15(4) may be allowed at the time of closure.
	135.15(4) Overexcavation of contaminated soils at closure.
	a. 	If contaminated soils are discovered while assessing a site at closure in accordance with 135.15(3), owners and operators may overexcavate up to one foot of the contaminated soils surrounding the tank pit. The contamination and overexcavation must be reported to the department in accordance with the requirements of 135.6(4)“a” prior to backfilling the excavation. If excavation is limited to one foot of contaminated soils, a soil sample shall be taken and laboratory analyzed in accordance with 567—135.16(455B) from the area showing the greatest contamination. Any overexcavation of contaminated soils beyond one foot of contaminated soils is considered expedited corrective action and must be conducted by a certified groundwater professional in accordance with the procedures in 135.12(11).
	b. 	Excavated contaminated soils must be properly disposed in accordance with 567—Chapters 100, 101, 102, 120, and 121, Iowa Administrative Code.
	c. 	A report must be submitted to the department within 30 days of completion of the laboratory analysis. The report must include the requirements of 135.15(3)“e” and a dimensional drawing showing the depth and area of the excavation prior to and after overexcavation. The area of contamination must be shown.
	135.15(5) Applicability to previously closed UST systems. When directed by the department, the owner and operator of a UST system permanently closed before October 24, 1988, must assess the excavation zone and close the UST system in accordance with this rule if releases from the UST may, in the judgment of the department, pose a current or potential threat to human health and the environment.
	135.15(6) Closure records. Owners and operators must maintain records in accordance with 135.4(5) that are capable of demonstrating compliance with closure requirements under this rule. The results of the excavation zone assessment required in 135.15(3) must be maintained for at least three years after completion of permanent closure or change-in-service in one of the following ways:
	a. 	By the owners and operators who took the UST system out of service;
	b. 	By the current owners and operators of the UST system site; or
	c. 	By mailing these records to the department if they cannot be maintained at the closed facility.
	135.15(7) Applicability to pre-1974 USTs. The closure provisions of rule 567—135.15(455B) are not applicable to USTs which have been out of operation prior to January 1, 1974. For purposes of this subrule, out of operation means that no regulated substance has been deposited into or dispensed from the tanks and that the tanks do not currently contain an accumulation of regulated substances other than a de minimis amount as provided in paragraph 135.15(1)“a.”
Owners and operators or other interested parties are not required to submit documentation that USTs meet the exemption conditions and may rely on this subrule as guidance. However, should a question arise as to whether USTs meet the exemption, or owners and operators or other interested parties request acknowledgment by the department that USTs are exempt, they must submit an affidavit on a form provided by the department. The affiant must certify that based on a reasonable investigation and to the best of the affiant’s knowledge, the USTs were taken out of operation prior to January 1, 1974, the USTs have not contained a regulated substance since January 1, 1974, and the USTs do not currently contain an accumulation of regulated substances.
If the department has a reasonable basis to suspect a release has occurred, the release investigation and confirmation steps of rule 567—135.6(455B) and the corrective action requirements as provided in rules 567—135.7(455B) through 567—135.12(455B) shall apply.
[ARC 8124B, IAB 9/9/09, effective 10/14/09; ARC 5625C, IAB 5/19/21, effective 6/23/21]