Site Assessment Requirements
(1)An owner and permittee must complete a site assessment to measure for the presence of a release where contamination is most likely to be present at the UST facility and must submit results of the assessment to DEQ when any of the following events occur:
(a)Decommissioning (OAR 340-150-0168 (General Permit Requirements for Decommissioning an UST System by Permanent Closure or Change-in-Service)); or
(b)Request for Extension of Temporary Closure Certificate (OAR 340-150-0167 (General Permit Requirements for Temporary Closure of an UST System)); or
(c)Underground piping is modified, decommissioned by removal, or abandoned; or
(d)Dispensers are moved, modified, decommissioned or abandoned unless the dispenser has under dispenser containment (UDC).
(2)In selecting sample types, sample locations and measurement methods, an owner and permittee 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.
(3)For USTs containing petroleum, the owner and permittee must measure for the presence of a release by following the sampling and analytical procedures specified in OAR 340-122-0205 (Cleanup Rules for Leaking Petroleum UST Systems: Purpose) through 340-122-0360 (Cleanup Rules for Leaking Petroleum UST Systems: Reporting Requirements) and section (5) of this rule.
(4)For USTs containing regulated substances other than petroleum, including waste oil tanks, petroleum USTs to be closed in-place, and USTs to undergo a change-in-service, an owner and permittee must submit a written site assessment plan (i.e., sampling plan) to DEQ and receive DEQ approval before beginning permanent closure or change-in-service. The plan must include the following information:
(a)A site diagram, drawn to scale, that identifies:
(A)The location of all USTs and underground piping, dispenser islands, buildings and nearby properties;
(B)All surface water bodies within 1⁄4 mile of the UST facility;
(C)Any potential conduits for spreading contamination that may exist (e.g., water or sewer lines); and
(D)All proposed sample locations, clearly marked.
(b)A list of analytical procedures and sample collection methods to be used;
(c)General information about the sample collector and UST facility;
(d)The location of all proposed sampling points that meet the requirements of section (5) of this rule; and
(e)Any other information as DEQ specifies.
(5)Unless DEQ directs or approves otherwise, an owner and permittee must meet the following requirements for sampling and analysis:
(a)Soil samples must be collected from the native soils located no more than two feet beneath the bottom of the tank pit in areas where contamination is most likely to be found;
(b)For in-place closure or change-in-service of an UST, a minimum of four soil samples must be collected, one each from beneath both ends of the tank and on each side;
(c)For the removal of a single tank, two to four soil samples must be collected as appropriate based on site conditions, including the condition of the removed tank;
(d)For the removal of multiple USTs from the same pit, in addition to subsection (c) of this section, one soil sample must be collected for each 100 square feet of area in the pit from areas where contamination is most likely to be found;
(e)For underground piping:
(A)For piping runs between 5 and 20 feet, a minimum of two soil samples must be collected from the native soils directly beneath the areas where contamination is most likely to be found, unless otherwise approved by DEQ; and
(B)For piping runs of more than 20 feet in length, beginning at the dispensers, at least one additional soil sample must be collected at each 20-foot interval.
(f)For dispensers, at least one soil sample must be collected from the native soils directly beneath each dispenser;
(g)For UST components (e.g., underground piping or dispensers) located directly above an area to be excavated, the area must be visually assessed before excavation work is conducted and soil samples collected if contamination is observed or suspected;
(h)All soil samples must be analyzed by the Northwest Total Petroleum Hydrocarbon Identification Analytical Method (NWTPH-HCID, DEQ, December 1996)) test specified in OAR 340-122-0218 (Cleanup Rules for Leaking Petroleum UST Systems: Sampling and Analysis)(1)(d)(A) to determine if a confirmed petroleum release exists; and
(i)If water is present in the UST pit, regardless of whether obvious contamination is present, DEQ must be notified within 24 hours of discovery.
(6)The guidance contained in Appendix K of this division may be used to comply with sections (4) and (5) of this rule.
(7)An owner and permittee must report a confirmed release to DEQ within 24 hours of confirmation by observance or receipt of analytical results. Upon discovery of a release, an owner and permittee must:
(a)Immediately initiate corrective action. An owner and permittee may request and DEQ may approve a specific time schedule to initiate corrective action on a case-by-case basis depending on the severity of the contamination or other relevant factors; and
(b)Follow the requirements of OAR 340-122-0225 (Cleanup Rules for Leaking Petroleum UST Systems: Initial Abatement Measures and Site Check) for “Initial Abatement and Site Check” and 340-122-0235 (Cleanup Rules for Leaking Petroleum UST Systems: Free Product Removal) for “Free Product Removal” as appropriate.
(8)An owner and permittee must submit a written report of the results of the site assessment to DEQ within 30 days after completing the field work or other period DEQ approves.
Rule 340-150-0180 — Site Assessment Requirements,