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Site Report: Alyeska Five Mile Airstrip


Site Name: Alyeska Five Mile Airstrip
Address: Milepost 60.7 Dalton Highway, ~5 Miles N Yukon River; ~55 Miles N of Minto, Minto, AK 99758
File Number: 330.38.119
Hazard ID: 25387
Status: Cleanup Complete
Staff: ,
Latitude: 65.930369
Longitude: -149.846036
Horizontal Datum:WGS84

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

Alyeska currently leases the property from BLM and wishes to return the property to the BLM now that the site is no longer in use. SLR conducted a Phase I on behalf of Alyeska as a component of landowner liability protections to CERCLA liability and to understand potential environmental conditions that could materially impact business operations located on the site. Access to the site is not controlled and has had unauthorized use such as by recreational campers; Alyeska is the only official occupant. Two soil samples collected were from ~6 inches bgs with results up to 3,820 mg/kg DRO and 25,900 mg/kg RRO.

Action Information

Action Date Action Description DEC Staff
3/13/2009 Report or Workplan Review - Other Receipt of Phase I Site Assessment Report and Preliminary Soil Testing. Alyeska currently leases the property from BLM and wishes to return the property to the BLM now that the site is no longer in use. SLR conducted a Phase I on behalf of Alyeska as a component of landowner liability protections to CERCLA liability and to understand potential environmental conditions that could materially impact business operations located on the site. Access to the site is not controlled and has had unauthorized use such as by recreational campers; Alyeska is the only official occupant. Two soil samples collected were from ~6 inches bgs with results up to 3,820 mg/kg DRO and 25,900 mg/kg RRO. Laboratory review checklist was not included. DEC review included laboratory data for quality issues. S1 DRO/RRO results should be considered estimated with a low bias. Analytical suite included VOCs and metals. Keather McLoone
4/8/2009 Site Added to Database A new site has been added to the database Mitzi Read
4/14/2009 Exposure Tracking Model Ranking Initial ranking with ETM completed for source area id: 78749 name: Transmission Pipeline Grant Lidren
6/4/2009 Cleanup Plan Approved Approval of Five Mile Airstrip 2009 Site Remediation Work Plan. Corrected draft submitted electronically. Alyeska plans to excavate approximately 20 cubic yards of contaminated soil. The excavation is anticipated to be shallow and cover about 450 square feet. Excavation will proceed until either no further contamination is evidenced thru field screening or permafrost, bedrock, or suprapermafrost ground water is encountered. Confirmation samples will be collected and analyzed for BTEX/GRO/DRO/RRO. Excavated soil will be stockpiled at PS 06 or placed into 55-gallon drums or supersacks (if the amount of excavated soil is small). Keather McLoone
7/25/2009 Update or Other Action Alyeska notified DEC that while excavating, it was discovered that the extent of contamination was much greater than anticipated. A meeting with BLM is anticipated to discuss next steps. Alyeska has placed a liner in the current excavation and anticipates requesting approval to backfill and finish the excavation effort next year. Surface water samples are planned if surface water nearby can be located. A CSM will be developed to help guide work in 2010. A site visit is planned to be conducted by DEC, Alyeska, and SLR. Keather McLoone
8/13/2009 Site Visit CS staff conducted a site inspection with Alyeska Pipeline Services Company, their consultant, and a representative of the Bureau of Land Management (BLM) at Alyeska Five Mile Airstrip. This site inspection was requested by Alyeska in order to discuss the status of a removal effort at this site and development of a Conceptual Site Model. A meeting is planned with DEC, Alyeska, SLR, and BLM for August 24th to discuss further actions. Keather McLoone
8/24/2009 Meeting or Teleconference Held Meeting with Alyeska and their consultant (SLR) and BLM regarding recent site visit and analytical results and next steps for this site. Recent analytical data suggests either 1)recent contamination OR 2)recent and historic contamination based on high levels of benzene etc. Keather McLoone
6/29/2010 Report or Workplan Review - Other Receipt of Five Mile Airstrip Site Remediation Report. Approximately 60 cubic yards of contaminated soil were removed, confirmation samples collected, and additional test pitting conducted to further delineate the extent of contamination remaining. Alyeska requested a Cleanup Complete for the site with permafrost bounding the area supporting arctic zone cleanup levels. Soil confirmation samples were collected at depths ranging from 2.5 to 15 ft bgs and contained up to 799 mg/kg GRO, 9,040 mg/kg DRO, 0.461 mg/kg benzene, 8.34 mg/kg ethylbenzene, 59.7 1-methylnaphthalene, 80.4 mg/kg 2-methylnaphthalene, and 52.9 mg/kg naphthalene. Thirteen samples and two duplicates were collected and the majority of results were less than most conservative cleanup criteria. Keather McLoone
7/12/2010 Cleanup Complete Determination Issued The Alaska Department of Environmental Conservation (ADEC), Contaminated Sites Program, has completed a review of the environmental records associated with the Alyeska Five Mile Airstrip site. Based on the information provided to date, the ADEC has determined that the contaminant concentrations remaining on site do not pose an unacceptable risk to human health or the environment, and no further remedial action will be required as long as the site is in compliance with established institutional controls. This decision is based on the administrative record for Alyeska Five Mile Airstrip, which is located in the offices of the ADEC in Anchorage, Alaska. Keather McLoone
7/13/2010 Institutional Control Record Established Institutional Controls established and entered into the database. Keather McLoone
7/8/2011 Meeting or Teleconference Held Meeting with Alyeska and SLR regarding the type of information that might show that permafrost could be considered continuous at this location. Keather McLoone
7/18/2011 Report or Workplan Review - Other Date of receipt of Five Mile Airstrip Structure Footprint Sampling Workplan. This document was provided as what they have called a "courtesy copy". This work is to confirm a clean location after removal of existing aboveground features as part of Alyeska's goal to get out of the current lease. These features are located on the other end of the airstrip and will be considered separate source areas should contamination be found. Earlier due diligence conducted by Alyeska did not identify a cause for concern associated with the features at the north end of the airstrip. Keather McLoone
7/26/2011 Report or Workplan Review - Other Date of receipt of Five Mile Airstrip Permafrost and 1975 VSM Summary document. Contains 2008 Alaska Permafrost Map, 1975 VMS Boring Locations, 1975 VSM Boring Summary, 1975 VSM Boring Logs - Lithology and Frozen Information Summary, and 1975 VSM Boring Logs - Originals. Keather McLoone
8/5/2011 Meeting or Teleconference Held Meeting with representatives of BLM (landowner) and Alyeska regarding the proposed arctic zone cleanup levels (which seem to have a good amount of data supporting). Followup required on part of Alyeska. DEC CSP was asked about requirements to request approval to transport material from the site. DEC CSP explained that this was a regulatory requirement for all contaminated sites and was not limited to sites that were given a Cleanup Complete with ICs decision. Keather McLoone
11/21/2011 Institutional Control Record Removed An amendment to the original decision letter was sent on this date as Alyeska provided information to satisfy both DEC and BLM that an arctic zone scenario was appropriate for this site. Keather McLoone
12/1/2011 Update or Other Action The current project manager chose to retain management of this site with the Cleanup Complete Determination that has Institutional Controls. Kristin Brown
5/14/2012 Report or Workplan Review - Other Date of receipt of Five Mile Airstrip Corrective Action Workplan. This sampling plan covers the ground beneath structures (a Tower/Firehouse, a former AST secondary containment, AND a former generator secondary containment) that have either been removed or will be removed from the north end of the airstrip (oppostie end from this site's "original" source area). This is an expansion of the plan from July 18, 2011 to now include 2 former ASTs at the south end of the airstrip. Sampling is being conducted to determine if contamination exists beneath structures that are being removed. This workplan is for information purposes only since this site was previously closed in 2010. Keather McLoone
11/5/2012 Report or Workplan Review - Other Date of receipt for October 2012 site characterization report. Although site is closed, several structures were removed after closure and soil beneath/around these areas was characterized, to include: an AST secondary containment area (northern end of airstrip), the soil beneath the airport tower/firehouse and former slab (northern portion of airstrip), and two AST areas in the southern portion of the airstrip). Alyeska field screened 84 soil samples and analyzed 23 soil samples. Field screening didn't reveal any areas of concern, and analytical samples did not identify evidence of contamination above ADEC cleanup levels. No further action is anticipated. Richard Bernhardt

Contaminant Information

Name Level Description Media Comments
DRO < Method 2 Most Stringent Soil based off Arctic Zone
RRO < Method 2 Most Stringent Soil based off Arctic Zone

Control Type

Type Details
No ICs Required

Requirements

Description Details
Advance approval required to transport soil or groundwater off-site.

Missing Location Data

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