Generic Remedy Clean-Up
A Generic Remedy Clean-Up is considered a mid-level contamination, consisting of a release of 501 – 10,000 PPM. This remediation is a soil-only clean-up as long as there is no impact to groundwater, no free product is present and there is no vapor intrusion into the home or building. A generic remedy may require soil removal, as well as additional soil samples around the tank to determine the extent of the contamination. Total Petroleum Hydrocarbon (TPH) concentrations up to, but not exceeding, 10,000 PPM of soil may be left in place if:
- There is at least three feet of clean soil over the contaminated soil
- The volume of remaining contaminated soil (over 500 PPM) does not exceed 65 cubic yards
- Analysis for the presence of benzene, ethylbenzene and naphthalene must be performed on all samples exceeding 2,500 PPM.
Once the investigation of the soils around the tank and the contaminated soil has been removed, the generic remedy clean-up decommissioning of the tank can continue.
In order to establish if a generic remedy is necessary, the DEQ requires a site assessment must be conducted to determine the source, nature, magnitude and extent of the contamination associated with a release from the underground storage tank. The site assessment must specifically address:
Generic Remedy Clean-Up Investigation
- Determine the presence of free product
- If there is pooling of liquid fuel in the tank excavation area or if there is clearly visible saturated soil, free product is present and a generic remedy remediation is no longer acceptable.
- Determine if groundwater is affected and the depth to groundwater
- During the tank excavation, if groundwater impact is discovered, the DEQ requires the water be pumped from the pit. If the pit remains dry for 24 hours, sampling and clean-up may proceed under the generic remedy. If water returns in less than 24 hours, it is presumed to be groundwater and the use of the generic remedy remediation is not allowed.
- Determine the vertical and horizontal extent of the heating oil contamination
- If decommissioning will be performed by removing the tank, two samples must be taken from each end of the excavation, at least 6 inches below the bottom of the excavation. If, by visual observations, additional contamination or odors are detected, samples must be collected from these areas as well.
- If the decommissioned tank is to stay within the ground, two soil samples are to be taken from each end of the tank, as well as one below the tank bottom. The samples are to be taken no more than six inches from the tank end and at least one foot below the tank bottom. If contamination or odors are encountered, based on visual observations, samples must also be collected from these areas as well.
- An estimated volume of contaminated soil proposed to remain at the site will be required to ensure that the 65 cubic yard limitation is not exceeded. Results of soil samples analyzed for the presence of heating oil are required to determine both the vertical and horizontal extent of contamination remaining above 500 PPM.
We have provided a link, this provides more insight to understanding more of the DEQs requirements regarding Generic Remedy Clean-Up remediation standards and guidelines.