(1)Unless the Department finds the UST site meets the decommissioning requirements in OAR 340, division 150 or the cleanup standards described in OAR 340, division 122 based upon currently available information, a person applying for financial assistance must assess the site for contamination in accordance with this section.
(2)One of the following site assessments shall be conducted and submitted to the Department for approval:
(a)A complete report of a site assessment conducted after December 22, 1988;
(b)A site assessment following the sampling method described in section (3) of this rule. The proposed sampling plan shall be submitted to the Department for approval before initiating any work;
(c)An alternate sampling plan and site assessment procedure determined by the applicant and approved by the Department before initiating any work.
(3)Unless otherwise approved by the Department pursuant to subsection (2)(c) of this rule, collect soil or water samples by boring or test pits:
(a)Where groundwater is not present, collect one sample in each boring or test pit from the native soils at an elevation below, but no more than two feet below, the bottom of any underground storage tank and from any soil that appears to be contaminated if encountered during installation of borings or test pits;
(b)Where groundwater is present, collect a soil and water sample at the soil/water interface in each boring or test pit;
(c)Borings or test pits shall be located along each side of an imaginary rectangular area drawn around an UST or group of USTs so that each side of the rectangle lies a maximum of three feet from the nearest UST:
(A)The imaginary rectangle may be drawn around a group of USTs when each UST is within six feet of an adjacent UST;
(B)A separate imaginary rectangle must be drawn around each UST that is located more than six feet from an adjacent UST;
(C)A minimum of one boring or test pit shall be located at the midpoint on each side of the imaginary rectangle. Where a side exceeds 15 feet, two or more borings or test pits shall be located equally spaced along the side. Borings or test pits shall not be located more than 25 feet apart along any side of the rectangle.
(d)Analyze the soil and/or groundwater samples in accordance with 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).
(4)The sample collection and analytical procedures shall meet the requirements of OAR 340, division 122.
(5)The site assessment must be performed under the direction or supervision of a licensed UST soil matrix supervisor, registered professional engineer, registered geologist, or a certified professional soil scientist (a soil scientist with certification and inclusion in the American Registry of Certified Professionals in Agronomy, Crops, and Soils, Ltd. (ARCPACS)).
Rule 340-172-0050 — Site Assessment,