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Site Report: Unalakleet Air. Warning - USTs

Site Name: Unalakleet Air. Warning - USTs
Address: No Address, Unalakleet, AK 99684
File Number: 630.26.001
Hazard ID: 25034
Status: Active
Staff: Axl LeVan, 9074512156 axl.levan@alaska.gov
Latitude: 63.918600
Longitude: -160.748100
Horizontal Datum:NAD27

We make every effort to ensure the data presented here is accurate based on the best available information currently on file with DEC. It is therefore subject to change as new information becomes available. We recommend contacting the assigned project staff prior to making decisions based on this information.

Problems/Comments

Two USTs were removed from the Unalakleet Aircraft Warning Site in 1995: a 10,000 gallon diesel tank and a 5,000 gallon gasoline tank. Site characterization after removal found contamination above cleanup levels remaining for the diesel UST at 10 - 13 feet below ground surface. No contamination was documented above cleanup levels for the gasoline UST after further excavation. A third UST noted in the UST records probably corresponds to a tank removed from the former Communications Building (TACAN) at the beach north of the town runway. The documented contamination as a result of this building and tank are being tracked under the Contaminated Sites database under the same site "Unalakleet Air. Warning Sta. / DERP". Update 11/1/2022: the site is being tracked under 630.38.003.

Action Information

Action Date Action Description DEC Staff
11/5/1998 Leaking Underground Storage Tank Release Confirmed - Petroleum LUST Site created in CSP for source area ID 78010 Corrected the FACID and action date Former Staff
11/5/1998 Site Added to Database Former Staff
1/4/2005 Update or Other Action Corrected the location of the former USTs in the database. Colin Craven
6/10/2005 Underground Storage Tank Site Characterization or Assessment The US Army Corps of Engineers is conducting site characterization at the former Aircraft Control and Warning station in the summer of 2005. Additional investigation will be conducted at the former diesel UST location. See the Contaminated Sites database entry for more details (under "Unalakleet Air. Warning Sta. / DERP"). Colin Craven
6/10/2005 Leaking Underground Storage Tank Cleanup Initiated - Petroleum The two USTs were removed in 1995 and contaminated soil was excavated and thermally remediated on site. Evonne Reese
3/28/2006 Document, Report, or Work plan Review - other The 2005 site characterization included test pits at the former location of the 10,000 gallon diesel UST. DRO was found above Method 2 cleanup levels ranging from 260 - 360 mg/kg at depths of 4 to 10 feet below the surface. Benzo(a)pyrene exceeded Method 2 cleanup levels at 10 feet below the surface in one boring. Site closure options will be discussed with the Army Corps in April 2006. Colin Craven
5/6/2008 Exposure Tracking Model Ranking Direct contact with subsurface soil is a de minimis exposure, all other pathways are incomplete. Kim DeRuyter
5/6/2008 Update or Other Action The ETM ranking applies to the USTs at site 25E. DRO was detected in soil between 4 and 10 feet below ground surface up to 360 mg/kg, Benzo(a)pyrene was also detected up to 2 mg/kg in these samples. Residual contamination is below Method 2 risk based cleanup levels, and is not readily accessible to site visitors. Kim DeRuyter
5/16/2008 Document, Report, or Work plan Review - other Received the Draft 2008 Feasibility Study. Kim DeRuyter
6/13/2008 Update or Other Action Sent letter in response to the Draft FS the letter describes ADECs proposed remedial actions at each source area. Kim DeRuyter
6/30/2008 Proposed Plan Received the Draft Proposed Plan, excavation and off site treatment is the the proposed remedial action at most sites. ADEC stated agreement in the June 13, 2008 Draft FS comment letter to NFA for the Barrel Bluff, Gravel Pit, Beach Road Drum Dump, Landfill by Air Force Road, Abandoned Fuel Truck, Barrel Disposal Area, Pump House 1 & 2, South Dome Tower, North and South Radar Buildings, Fuel Filling Station, Sewage Treatment Plant and Outfall, and Former Landfill sites. After the letter was sent ADEC took a second look at the Tranformer Storage Area and determined site characterization for this area was adequate, and NFA was required at this former source area. This was addressed in a teleconference with the ACOE. Kim DeRuyter
7/7/2008 Site Visit A site visit was conducted to most of the source areas prior to the RAB meeting. The Communication Building site which had DRO Contamination up to 14,000 ppm could not be located, it appears to have been covered with pavement by ADOT during improvements to the access road to the airport. The consultant will review the records to determine if GPS data is available for the site. An additional drum with product, and numerous lead-acid batteries and a compressed gas tank were found near one of the Musk Ox Farm buildings. It is unclear if this potential source area is of military origin. Kim DeRuyter
7/7/2008 Meeting or Teleconference Held RAB meeting held to discuss the feasibility study and proposed plan for the site. The community members expressed concern about potential contaminant runoff into anadromous streams. After the RAB meeting, DEC staff spoke with several community members about the proposed relocation of the community further up the hill toward the Aircraft Warning Site. Several Community members mentioned that the community had already started moving and that new drinking water wells were being installed. It was unclear how far up the hill the residents intended to relocated, but one person said that the UNC had plotted lots along most of Army Road. When discussing the drinking water wells, a community member mentioned that the Alaska Community Action on Toxics had sampled the new wells recently, though which wells and when the samples were collected or what they were sampled for was not clear. Kim DeRuyter
8/21/2008 Update or Other Action Sent comment letter on the Draft Final Feasibility Study. Requested that the proposed cleanup levels be applied to the feasibility study, as they will be promulgated prior to the signing of decision documents at this site. Requested the ACOE address the additional source areas at the Musk Ox Farm discovered during the site visit earlier this summer. Also requested that the ACOE gather existing data on groundwater wells near source areas, such as location, depth, previous sampling results. Asked that the ACOE request information from the Unalakleet Native Corporation on the proposed relocation of the community. Kim DeRuyter
9/11/2008 Meeting or Teleconference Held Met with the ACOE and ENSR to discuss the 8/21/08 letter. It was agreed that the revised cleanup levels could be used as cleanup goals for the site, without revising the FS, or reviewing prior remedial action because the petroleum and PCB cleanup levels haven't changed, and the contaminants at the site that have newly revised cleanup levels, TCE, PAHs are not wide spread and are expected to be excavated and treated offsite during the planned remedial action next summer. The ACOE agreed to cleanup the one additional drum with product located at the Musk Ox Farm, but they will not cleanup the batteries or gas cylinder as they believe they were part of the farm operation. The ACOE did agree to assess the migration to groundwater pathway prior to the signing of decision documents. Kim DeRuyter
2/28/2011 Update or Other Action Spoke with USACE PM Ron Pflum. He stated that cleanup actions under the 2010 Remedial Action Plans did not get finished this summer because funds ran out. DEC requested a letter report that summarizes the activites that were accomplished, activities that are planned to be accomplished during the 2011 field season, and any work plan deviations. He also stated that cleanup will likely be put off until 2012 due to lack of funding. Amanda Loomis
3/1/2011 Update or Other Action Scope of Work for the modification to the existing Unalakleet RA project recieved from USACE. Letter also stated that a letter report on the work completed last year will be sent to DEC once it is recieved from the contractor. Amanda Loomis
8/7/2015 Update or Other Action Cross reference this site to 630.38.003 Unalakleet Aircraft Warning Site FUDS. Multiple sites included. USTs addressed during work in 2011 - 2015. Current status of UST site is evaluate for closure. Fred Vreeman
4/26/2016 Update or Other Action Site reassigned for evaluation of cleanup requirements, and follow up by project manager for other Unalakleet federal sites. Fred Vreeman
11/1/2022 Update or Other Action DEC reviewed the site footprint based on past excavations and the decision document for site 630.38.003, under which this site has been tracked since 2016. The previous footprints of the USTs fall within known contamination from 630.38.003 that is planned for treatment by phytoremediation. This is expected to treat the PAHs remaining at the site. Axl LeVan

Contaminant Information

Name Level Description Media Comments

Control Type

Type Details

Requirements

Description Details

There are no documents for this site report.

Hazard ID Site Name File Number
849 Unalakleet Air. Warning - Main Radar Site 630.38.003

Missing Location Data

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