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Site Report: FAA McGrath Building 604

Site Name: FAA McGrath Building 604
Address: Airport, East of Runway, SE of Runway Intersection, McGrath, AK 99627
File Number: 2612.38.001
Hazard ID: 2119
Status: Active
Staff: Sophia Bracio, 9074511682 sophia.bracio@alaska.gov
Latitude: 62.956998
Longitude: -155.600557
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

Last Updated: December 11, 2017 Note: Building 305 and Building 604 are adjacent to one another Contamination from both sites is overlapping. Utility Building 604 is located adjacent to Building 305 (Station Maintenance Shop Building). The source area encompasses former tank locations at both Buildings 305 and 604. In 1993, three underground storage tanks (UST; UST 16-B-9, UST 16-B-10, and UST 16-B-14) were decommissioned and replaced by four new USTs (UST 16-B-109, UST 16-B-115, UST 16-B-110, and UST 16-B-114). During the 1993 decommissioning activities, hydrocarbon-contaminated soils were encountered. Approximately 270 cubic yards of contaminated soil was excavated from the location of UST 16-B-9; the Building 305 UST location; and the Building 605 heating oil tank location. A 1994 investigation identified impacted soil and groundwater surrounding the locations of the former USTs. In 1996, an in-situ bioventing system was installed at the Shop Building 305/Former Utility Building 604 site to address contamination. The system was operational until 2004. A second RI was conducted in 2011. A non-aqueous phase liquid (NAPL) contaminated soil source area was identified as extending from the Building 305 heating oil UST location to the Building 604 heating oil UST location (about 120 feet). The NAPL-contaminated soil extends from approximately seven to 20 feet bgs. The deepest contamination was found near the Building 305 heating oil tank. Soil samples were collected from Building 305/604 in 2011. Based on those results, DRO, ethylbenzene, xylene, naphthalene, 1-methylnaphthalene, and 2-methylnaphthalene concentrations exceeded the 2016 ADEC Method 2 Migration to Groundwater cleanup levels. Groundwater monitoring was conducted at Building 305/604 in 2011, 2012, and 2013. All groundwater samples were analyzed for BTEX, GRO, DRO, and RRO. Additionally, groundwater samples from three of the source area wells were also analyzed for PAH, EPH, and VPH. In 2011 and 2012, one sample each exceeded the November 2016 Table C Groundwater cleanup levels for DRO and 1-methylnaphthalene. In 2011, 2012, and 2013, one sample exceeded the Table C groundwater cleanup levels for naphthalene.

Action Information

Action Date Action Description DEC Staff
7/9/2003 Site Added to Database DRO contamination. Deborah Williams
7/9/2003 Site Ranked Using the AHRM Preliminary ranking. Deborah Williams
7/14/2003 Update or Other Action ADEC approved a workplan with the following scope of work: Decommissioning of monitoring wells from prior remedial investigations, MW-7 at the RCAG and MW-11 at the NDB. Site investigation to determine the extent of contamination discovered at the former treatment cell location. Monitoring and evaluation of the active Hobby Shop SVE system. Monitoring and evaluation of the active SVE system at Building 305/604. Subsurface soil sampling at the former Power House. Implementation of long-term groundwater monitoring at the former tank farm. Investigate petroleum contamination on the private property at the former tank farm. Evaluation of natural attenuation along former pipeline and at the former FSS. Survey the monitoring wells in the quarters and tank farm area and prepare a groundwater contour map. Removal of abandoned pipeline and relase investigation. Deborah Williams
6/9/2005 Meeting or Teleconference Held ADEC received a Site Investigation and Remedial Evaluation Report. The report includes recommendations based upon outputs of Geosphere's 4-phase model and recommends no further remedial action at several sites where contaminant concentrations exceed the maximum allowable limit of 12,500 mg/kg DRO. The 4-phase model has not yet been verified for accuracy. ADEC discussed this with the FAA and will recommend that siol above the maximum allowable concentration be removed during airport upgrades tentatively scheduled for summer 2006. Sharon Richmond
7/28/2005 Site Characterization Report Approved Contaminated Sites (CS) staff reviewed and provided comments to the Federal Aviation Administration's Site Investigation and Remedial Evaluation Report at the McGrath Airport. Numerous areas contaminated with petroleum were addressed during this investigation. Several air sparge/soil vapor extraction systems have been operating but recovery of fuel has diminished because volatile fuel components have been mostly removed; these systems will be shut down and decommissioned. Other areas still have residual diesel contamination but, in general, concentrations of benzene, toluene, ethylbenzene, and xylenes are below cleanup levels in soil and groundwater. Contamination that has migrated off-site will be excavated and managed as part of remedial efforts at the former tank farm area. CS staff recommended that all soil with contamination above the maximum allowable concentration be excavated and that a treatment strategy be developed. A resident of McGrath contacted the Department regarding off-site contamination.The individual was provided with a copy of the report and the comment letter. Sharon Richmond
1/26/2006 Update or Other Action All work performed for the Federal Aviation Administration (FAA) requires completion and approval of a Project Environmental and Occupational Safety and Health Worksheet (EOSH Worksheet). The EOSH Worksheet is a tool that allows project managers to identify potential hazards and contamination, take appropriate measures to avoid hazards and manage contamination appropriately, to minimize environmental impacts, determine whether environmental assessment is required prior to beginning work, and to minimize fines and/or penalties associated with non-compliance with federal and state regulations. It also acts a mechanism to identify when outside agency permits are necessary. Specific portions of the EOSH Worksheet address: the presence/absence of endangered species, activities conducted in wetlands or anadromous streams, whether work will occur on a contaminated site or involve activities associated with fuel tanks, fuel distribution lines, oil-containing transformers, groundwater monitoring wells, floor drains, and generation and handling of hazardous waste. To ensure all issues are appropriately considered, the worksheet is to be reviewed after each phase of project development and implemenation. This form is to be kept with project progress documents throughout the project. Sharon Richmond
1/12/2010 Exposure Tracking Model Ranking Initial ranking with ETM completed for source area id: 73097 name: FAA McGrath Building 604 Melody Debenham
8/2/2011 Site Characterization Workplan Approved Approved the Final Work Plan, Federal Aviation Administration (FAA) Release Investigation, FAA Station, McGrath, Alaska, describing investigation activities at 14 areas of concern at the FAA McGrath Station. An Ultra-Violet Optical Screening Tool (UVOST)/laser-induces fluorescence (LIF) probe will be used as a screening tool to investigate the horizontal and vertical extent of petroleum contamination. Locations of soil borings and groundwater monitoring wells will be determined based on site conditions and the UVOST/LIF screening results. Melody Debenham
5/16/2014 Document, Report, or Work plan Review - other Approved final 2013 groundwater monitoring report at 8 areas of concern. Results from Shop Building 305/Utility Building 604 are below cleanup levels. Melody Debenham
2/23/2015 Document, Report, or Work plan Review - other Approved final 2013 release investigation at 11 areas of concern. Sample results at the Shop Building 305/Former Utility Building 604 UST site shows contaminated soil and groundwater remain at this site. Melody Debenham
12/9/2016 Update or Other Action Teleconference with FAA project manager to discuss future actions at FAA McGrath sites. Melody Debenham
4/19/2017 Document, Report, or Work plan Review - other Letter sent to FAA advising that no response is required for the Department's December 2016 correspondence. Since multiple AOCs were evaluated using the HRC, ADEC will not be able to use the July 2016 report as a basis for decision making. ADEC will re-evaluate FAA McGrath AOCs that appear ready for closure. Some sites may be eligible for cleanup based on a cumulative risk evaluation. Other sites require additional investigation and/or remediation by FAA. Jamie McKellar
12/11/2017 Exposure Tracking Model Ranking A new updated ranking with ETM has been completed for source area 73097 FAA McGrath Building 604. Jamie McKellar
7/25/2024 Meeting or Teleconference Held On 7/23/2024, DEC met with FAA and their contractor regarding planned soil sampling at FAA McGrath. FAA's contractor is mobilizing to McGrath in fall 2024 to collect soil and groundwater samples. The intent of the mobilization is to evaluate FAA's sites for the presence/absence of PFAS in future excavation areas that are currently slated for remediation via landfarming. Jamie McKellar
10/7/2024 Site Characterization Workplan Approved WORK PLAN APPROVAL: Final Work Plan McGrath FAA Station PFAS Investigation (Brice, October 2024). Sophia Bracio

Contaminant Information

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Control Type

Type Details

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Description Details

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