OAR 340-170-0020
Soil Assessment
(1)
Soil assessment at a facility where underground storage tanks contain an accumulation of motor fuel shall be conducted by the property owner, UST owner or permittee in accordance with OAR 340, division 122 and sections (2) and (3) of this rule.(2)
Conduct an inspection of the UST facility to:(a)
Look for warning signs that indicate possible soil or water contamination due to spills or leakage from underground tanks.(b)
Check with owners of adjacent property to see if they have observed petroleum taste or odor in drinking water, petroleum fumes in their basement or buildings, or other unusual conditions that could be caused by motor fuel;(c)
Review UST inventory control and UST repair records for indications of releases from the USTs; and(d)
Prepare a written record of the inspection results.(3)
In situations where the tanks and lines are to remain in place, the property owner, tank owner, or the permittee shall:(a)
Submit a specific soil sampling plan to the Department for approval prior to initiating any work; or(b)
Collect soil 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;(B)
Where groundwater is present, collect two samples in each boring or test pit, the first sample within the first six inches of saturated soil and the second sample at an elevation below, but no more that two feet below, the bottom of any underground storage tank;(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:(i)
The imaginary rectangle may be drawn around a group of USTs when each UST is within six feet of an adjacent UST;(ii)
A separate imaginary rectangle must be drawn around each UST that is located more than six feet from an adjacent UST;(iii)
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 fifteen 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 twenty-five feet apart along any side of the rectangle.(D)
Analyze the soil and/or ground water samples in accordance with section (1) of this rule.
Source:
Rule 340-170-0020 — Soil Assessment, https://secure.sos.state.or.us/oard/view.action?ruleNumber=340-170-0020.