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Site Report: FAA Unalakleet - SBRAZ

Site Name: FAA Unalakleet - SBRAZ
Address: 2.5 Miles East of Unalakleet, Unalakleet, AK 99684
File Number: 630.38.004
Hazard ID: 4234
Status: Cleanup Complete
Staff: No Longer Assigned, 9074655229 dec.icunit@alaska.gov
Latitude: 63.869900
Longitude: -160.717300
Horizontal Datum:NAD83

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

The location of a former gasoline above ground tank was found to be saturated with the fuel during a 1992 environmental compliance investigation. Surface soil sampling documented toluene and ethylbenzene above Method 2 cleanup levels, and PAHs above screening levels. This site was a former radio range, but is currently inactive with all the towers removed. Existing site features include an abandoned generator building. The petroleum contamination will be characterized in 2007, and the area will also be screened for potential PCB contamination. On July 2, 2015, DEC finalized a Summary of Determinations: FAA Unalakleet – Direction Finder (DF) West Spill, DF East Spill, Range (SBRAZ) Transformer, and VORTAC Transformer. DEC reviewed the environmental records for the referenced sites in response to a Federal Aviation Administration (FAA) closure request letter, dated May 1, 2013. No further remedial action is required at these areas of concern. This site will remain active in the DEC contaminated sites program database, as there are separate source areas which have not been given a “cleanup complete” determination. The site is currently referred to as the Range Site. September 2017 Final Summary Report: Decommissioning, Remediation, and Site Investigation documented excavation activities west of the Former Transmitter Building. DRO and RRO remain above the alternative cleanup levels (approved 2018) at the limits of the excavation. 2021 Update: Site has been issued a cleanup complete determination on October 25, 2021. All remaining contaminants are well below applicable human health cleanup levels. Remaining contaminants in soils are: DRO, RRO, PCBs, Lead, Toluene, Ethylbenzene, Naphthalene and 2-methylnaphthalene. Groundwater cleanup levels do not apply to this site, per the March 2016 DEC issued letter to FAA acknowledging the presence of continuous permafrost in this area acting as a barrier for soil contaminant migration to groundwater. Letter is attached to site file.

Action Information

Action Date Action Description DEC Staff
4/27/2006 Site Added to Database Site added to the database. Mitzi Read
3/5/2007 Exposure Tracking Model Ranking Initial ranking. Lisa Maserjian
3/21/2008 Update or Other Action Received the Draft 2007 RI Report. PCBs were not detected in samples taken from the SBRAZ fromer transformer location. Fuel contamination remains in the area beneath the former AST exceeding Ingestion and Inhalation cleanup levels for DRO and RRO. The former AST was located in a wetland area and permafrost was present 2.5 feet below ground surface. Kim DeRuyter
3/21/2008 Update or Other Action ETM ranking updated based on the 2007 RI. Kim DeRuyter
12/2/2014 Update or Other Action Assigned site to new PM for FAA Unalakleet. Fred Vreeman
5/28/2015 Exposure Tracking Model Ranking A new updated ranking with ETM has been completed for source area 78338 SBRAZ Former Transformer . Monte Garroutte
7/2/2015 Update or Other Action The Alaska Department of Environmental Conservation (DEC) finalized a Summary of Determinations: FAA Unalakleet – Direction Finder (DF) West Spill, DF East Spill, Range (SBRAZ) Transformer, and VORTAC Transformer. DEC reviewed the environmental records for the referenced sites in response to a Federal Aviation Administration (FAA) closure request letter, dated May 1, 2013. At the Range (SBRAZ) area, during the 2007 RI, eight soil samples were collected from surface soil in the area where the former transformer was located and were analyzed for PCBs. No PCBs were detected. There are no other COCs at the site, therefore, this site will receive a “Cleanup Complete” designation on the Contaminated Sites Database. No further remedial action is required at this area of concern. The site identified by the site number 630.38.004, with Hazard ID 4234: FAA Unalakleet – SBRAZ will remain active in the DEC contaminated sites program database, as there are separate source areas at this site which have not been given a “cleanup complete” determination. Monte Garroutte
8/11/2015 Site Characterization Workplan Approved DEC approved the Final Work Plan, Decommissioning Infrastructure and Investigating/Remediating Contaminated Soil FAA Unalakleet Station, Alaska. The purpose and objectives of the planned work are to: 1) remove unused and associated debris from the Range Site and CT site and remove towers and ceilometers from the Unalakleet Airport, 2) investigate the nature and extent of contamination at the Range, CT, and VORTAC Drum Storage area sites, 3) excavate soil that exceeds DEC Method 2 cleanup levels from the CT and Range Sites; and 4) test transformer oils and sample soil for presence of PCBs at the VASI and LOC locations. Bethel plans to execute field work for this project in two phases. The first phase will be executed during the summer/fall 2015 field season and will include all field work associated with removing two ceilometers and DF towers/infrastructure from the Unalakleet airport, consolidating debris and infrastructure into piles at the Range and CT sites for winter transport off site, delineating contaminated soil at the Range and CT sites for winter excavation and transport off site, conducting a permafrost study, sampling transformer oil and soil for PCBs at the VASI and Localizer sites, and investigating the extent of contaminated soil at the VORTAC Drum Storage Area. Monte Garroutte
3/21/2016 Site Characterization Workplan Approved DEC approved the Work Plan Addendum, Decommissioning Infrastructure and Investigating/Remediating Contaminated Soil, FAA Unalakleet Station, Alaska. This work plan addendum reports findings of Phase 1 work that affect the execution of the second and third phases of work (Phase 2 and Phase 3) and describes the associated work. Phase 2 is scheduled to begin in late March 2016 and Phase 3 in June 2016. The purpose of the proposed work is to decommission and remove FAA infrastructure in the vicinity of Unalakleet that is no longer in use and to investigate/remediate contamination resulting from operations at the sites. Work was fully completed at the Direction Finder (DF), two ceilometers at the airport, and the Very High Frequency Omnidirectional Range Collocated Tactical Air Navigation (VORTAC) Drum Storage Area during Phase 1. Work remains to be conducted at four sites, including the Range Site (also referred to as the SBRAZ Site), Communication Transmitter (CT) Site, Visual Approach Slope Indicator (VASI), and Localizer (LOC). Phase 2 work includes 1) the removal of unused and associated debris from the Range Site and CT Site; 2) The excavation of petroleum-contaminated soil that exceeds DEC Method 2 Human Health cleanup levels from the Range Site; and 3) testing transformer oils for PCBs at the VASI and LOC locations. Phase 3 includes 1) Field screening and sampling for lead at the site of two fallen towers at the CT Site; 2) Sampling soil for presence of PCBs at the VASI and LOC locations if the transformer oil is positive for PCBs in Phase 2; 3) Excavation of PCB-contaminated soil at the CT site; 4) Monitoring of the tundra disturbance and surface water quality at the Range Site following the Phase 2 excavation and backfill. Monte Garroutte
3/21/2016 Cleanup Level(s) Approved A portion of the 2015 work at this site included a permafrost investigation. This permafrost investigation determined that the subsurface at the Range Site is underlain by continuous permafrost, and therefore the ADEC Policy for Establishing Cleanup Levels for Sites in the Arctic Zone In Accordance With 18 AAC 75, Article 3 Tech Memo, SPAR 99-3 (1999) is applicable for determining site cleanup levels. DEC has determined that the proposed application of Method Two Human Health cleanup levels for contaminated soil at the Range Site are approved as applicable cleanup levels pending additional surface water monitoring to be completed in Summer 2016 or 2017, following the stabilization of the disturbed area. In addition to surface water monitoring, tundra regrowth at the site should also be monitored in accordance with the ADEC Tundra Treatment Guidelines. The approval letter for this determination is attached to this site’s database entry. Monte Garroutte
11/6/2017 Update or Other Action Approved Decommissioning, Remediation, and Site Investigation Report 2017 addressing five areas of concern including the Range Site, Communication Transmitter (CT) Site, Very High Frequency Omnidirectional Range Collocated Tactical Air Navigation (VORTAC) Drum Storage Area, Visual Approach Slope Indicator (VASI), and Localizer. Site investigations led to remediation efforts at the Range Site and CT Site with 30 cubic yards and one cubic yard of soil removed, respectively. Petroleum contamination remains at the Range Site with concentrations of DRO ranging 263–151,000 mg/kg and RRO ranging 2,240–12,900 mg/kg, both results with silica gel cleanup. Lead contamination remains at the CT Site with the highest concentration at 56,900 mg/kg, in addition to minimal PCB contamination above cleanup levels (1.2 mg/kg). Contamination at the remaining AOCs is below cleanup levels. DEC concurs that additional work will be required at the Range Site and lead remaining at the CT will have to be addressed through remediation or ICs. Gretchen Caudill
8/27/2018 Document, Report, or Work plan Review - other WP reviewed and comments provided for Range (SBRAZ) and CT sites. Objectives listed include: the delineation of and removal of remaining fuel contamination at the Radio Range Site, mitigation of the lead-based paint chips at the CT site, and characterization of area beneath the former towers that were painted with lead based paint. Gretchen Caudill
2/21/2019 Document, Report, or Work plan Review - other DEC Approval of 2018 RA and RI for 2 sites - CT Towers and Radio Range Site. Gretchen Caudill
5/4/2021 Document, Report, or Work plan Review - other Completed review of Remedial Investigation and Remedial Action at Two Sites at the FAA Unalakleet station. Report detailed third phase of project, covering investigation and removal of contaminated soils at the Radio Range (SBRAZ) site and the Communication Towers (CT) site. Contaminated soils were removed fromteh SBRAZ and CT sites in addition to approx. 150 pounds of lead-based paint chips. Confirmation sample results from excavation margins are below Method Two Cleanup Levels. Report is approved. Kelly Walker
10/7/2021 Exposure Tracking Model Ranking A new updated ranking with ETM has been completed for source area 78151 SBRAZ AST. Kelly Walker
10/26/2021 Cleanup Complete Determination Issued Site has been issued a cleanup complete determination on October 25, 2021. All remaining contaminants are well below applicable human health cleanup levels. Remaining contaminants in soils are: DRO, RRO, PCBs, Lead, Toluene, Ethylbenzene, Naphthalene and 2-methylnaphthalene. Groundwater cleanup levels do not apply to this site, per the March 2016 DEC issued letter to FAA acknowledging the presence of continuous permafrost in this area acting as a barrier for soil contaminant migration to groundwater. Letter is attached to site file. Kelly Walker
10/26/2021 Institutional Control Record Removed Institutional Controls have been removed. Kelly Walker

Contaminant Information

Name Level Description Media Comments
DRO Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation Soil Remaining concentration of DRO on site is 1,780 mg/kg. Migration to groundwater cleanup levels do not apply at this location due to the presence underlying continuous permafrost.
RRO < Method 2 Most Stringent Soil Remaining concentration of RRO on site is 7,970 mg/kg. Migration to groundwater cleanup levels do not apply at this location due to the presence underlying continuous permafrost.
PCBs - Total < Method 2 Most Stringent Soil Remaining concentration of PCBs on site is 0.226 mg/kg. Migration to groundwater cleanup levels do not apply at this location due to the presence underlying continuous permafrost.
Lead - Total < Method 2 Most Stringent Soil Remaining concentration of total lead on site is 310 mg/kg. Migration to groundwater cleanup levels do not apply at this location due to the presence underlying continuous permafrost.
Toluene < Method 2 Most Stringent Soil Remaining concentration toluene on site is 0.339 mg/kg. Migration to groundwater cleanup levels do not apply at this location due to the presence underlying continuous permafrost.
Ethylbenzene < Method 2 Most Stringent Soil Remaining concentration of Ethylbenzene on site is 0.0316 mg/kg. Migration to groundwater cleanup levels do not apply at this location due to the presence underlying continuous permafrost.
Naphthalene Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation Soil Remaining concentration of naphthalene on site is 0.305 mg/kg. Migration to groundwater cleanup levels do not apply at this location due to the presence underlying continuous permafrost.
2-Methylnaphthalene < Method 2 Most Stringent Soil Remaining concentration of 2-methylnaphthalene on site is 0.660 mg/kg. Migration to groundwater cleanup levels do not apply at this location due to the presence underlying continuous permafrost.

Control Type

Type Details
No ICs Required

Requirements

Description Details
Advance approval required to transport soil or groundwater off-site.
Movement or use of contaminated material (including on site) in a manner that results in a violation of the water quality standards is prohibited (18 AAC 70)

No associated sites were found.

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State of Alaska Department of Environmental Conservation

P.O. Box 111800
Juneau, AK 99811-1800
Phone: 907-465-5066
Fax: 907-465-5245
TDD: 800-770-8973
Physical Location: 410 Willoughby