Underground Storage Tanks (UST's)

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It is the policy of the Hoopa Valley Tribe to implement a program to investigate and cleanup groundwater pollution caused by the unauthorized releases of petroleum from underground tanks in order to protect water quality while at the same time minimize the cost to responsible parties and the public in general.

On July 16, 1989, the Hoopa Valley Tribe applied for treatment as a state under the Water Pollution Control Program, authorized under Section 106 of the Clean Water Act. After determination that the necessary criteria were met, the United States Environmental Protection Agency (U. S. EPA) announced formal approval on July 3, 1990. The Hoopa Valley Tribe became the first Tribe in California to qualify for state status under Section 106. In July 1997, the Hoopa Valley Tribe completed the Water Quality Control Plan (WQCP) for waters of the Reservation. Inclusive in the WQCP are standards dealing with the closure of UST’s. For the past seven years, the Hoopa Tribal Environmental Protection Agency has been directly involved in the closure of over twenty UST sites within the Reservation. TEPA produced a handbook entitled How to Comply with the United States Environmental Protection Agency's Undergroung Storage Tank Regulations to assist private UST owners in meeting EPA's and Tribal standards. The Reservation's UST tank inventory included a combination of private, municipal, and Tribal tanks that were not in compliance for proper UST installation. In the case of private UST owners, TEPA provided direct technical assistance in meeting the upgrade requirement date of December 22, 1998 established by EPA. For Tribally owned UST's, TEPA developed closure plans, initiated closure activities, collected soil samples, and generated closure reports.

Excavating two leaking UST's and preparing cavity for soil samples

Five underground storage tanks were removed by TEPA staff and contractors in three locations within the Hoopa Valley Indian Reservation in 1998. First a licensed contractor exposed all five tanks, removed residual product and sludges and
applied a rinsate. Both diesel and gasoline were removed from the various sites and placed into 50 gallon barrels for disposal at an approved rendering and/or disposal facility. Sludges and sediments were also removed and stored in the same manner.
After rinsate was applied to all tanks, a 3 X 3 foot opening on top of the tanks were cut and the interior of the tanks were scrubbed and cleaned to bare metal. A local Tribal-member owned licensed contractor was utilized to excavate the tank areas and remove the tanks to the Cal-Pac storage area where they will be used for storage of non-potable water for fire protection after they are placed in the woods.

Sampling soil after removal of UST

Cleaned UST's

Cleaned UST's that will used for forest fire protection TEPA staff then conducted soil sampling prior to the backfilling of the tank cavities. After samples were manifested and lab results obtained, then the local contractor utilized structural fill and compacted the fill to 80 percent compaction levels. The three sites were then brought to grade for drainage purposes. Samples were obtained, labeled, iced and manifested to North Coast Laboratories for an analytical report. Constituents analyzed included the following:

THP - Gasoline THP - Diesel
BTEX (Additives) including:
MTBE
Benzene
Toluene
Ethlybenzene

Leaking UST

O-Xylene Blind samples, spikes and surrogates were also included in the laboratory analysis. The surrogate used for BTEX was Cis-1,2-Dichloroethylene and N-Tricosane for Diesel. Laboratory testing was done using EPA Method 8021B/5035 for BTEX, EPA 5035/GCFID for THP-Gasoline and EPA 3550/GCFID for Diesel. The Water Quality Standards of the Hoopa Valley Tribe has established a maximum concentration level (MCL) of 100 ppm for all three constituents for soil abatement. In one case, soil was contaminated at levels above 100 ppm. In this case, in-situ bio-remediation using a peat product was utilized to reduce the levels of contamination.

EPA's UST Web Page

Inter-Tribal Environmental Council's UST Page