Site Report: NPS Denali Nat'l Park HQ Bldg 27
| Site Name: | NPS Denali Nat'l Park HQ Bldg 27 |
|---|---|
| Address: | Headquarters Building 27, Denali Park, AK 99755 |
| File Number: | 220.38.015 |
| Hazard ID: | 25281 |
| Status: | Cleanup Complete - Institutional Controls |
| Staff: | IC Unit, 9074655229 dec.icunit@alaska.gov |
| Latitude: | 63.721426 |
| Longitude: | -148.963043 |
| Horizontal Datum: | WGS84 |
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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
A single wall heating oil above ground storage tank (AST) that serviced both building 27 and 28 was removed and replaced with an individual dual wall tank in 2004. On June 20, 2005, NPS began excavation of contaminated soils along the abandoned fuel oil lines from building 27 to the site of the old AST. Approximately 150 cubic yards of DRO contaminated soil were excavated from the site. Contamination was determined to be very sporadic and as a result, field screening was increased from one event for every 5 cubic yards to every cubic yard of soil removed. When the limits of the excavation were reached, confirmation samples were taken from each side wall, one from the floor of the excavation and one from the top of the boulder where the boulder limited the depth of the excavation. Confirmation soil samples were analyzed for BTEX and DRO. Confirmation sampling indicated that all wall samples were below cleanup levels. The floor samples on the boulder and at the bottom of the excavation had DRO up to 14,000 ppm DRO at 7 feet bgs.
Action Information
| Action Date | Action | Description | DEC Staff |
|---|---|---|---|
| 12/1/2008 | Site Added to Database | A new site has been added to the database | Mitzi Read |
| 12/2/2008 | Exposure Tracking Model Ranking | Initial ranking with ETM completed for source area id: 78620 name: Building 27 AST | Deborah Williams |
| 5/23/2012 | Site Visit | Performed a site visit at the C-Camp Auto Shop site and the C Camp Emergency Services/Fire Management Building site in Denali National Park & Preserve. National Park Service (NPS) staff gave us a tour of the C-Camp sites, sites in the Headquarters area and the Hotel Powerhouse site. At the C-Camp site we observed drilling and soil sampling for the installation of a monitoring well. | Melody Debenham |
| 8/17/2012 | Document, Report, or Work plan Review - other | Approved the final conceptual site model and vapor intrusion work plan for Headquarters Buildings 27, 28, and 34. An aboveground storage tank (AST) that served buildings 27 and 28 was removed in 2004. Contamination was left in place at the edge of the paved driveway near building 27, with a maximum concentration of 14,000 mg/kg DRO. This work plan includes the installation of two soil vapor probes to assess the presence of an oxygen barrier between the remaining soil contamination and building 27. | Melody Debenham |
| 8/17/2012 | Conceptual Site Model Submitted | Received conceptual site model (CSM) for Building 27. The CSM identifies direct contact with contaminants in soil inhalation of outdoor and indoor air as potentially complete pathways. | Melody Debenham |
| 1/17/2013 | Document, Report, or Work plan Review - other | Approved the final 2012 Denali Headquarters Building 27, 28, and 34 Vapor Intrusion Assessment Report. As part of the vapor intrusion assessment, consultants for the NPS performed a building survey at Building 27 and interviewed NPS staff and building residents. Due to equipment failure, soil vapor probes were not installed at Building 27. During the building survey it was discovered that all three buildings have operating radon mitigation systems in place, which effectively controls the vapor intrusion pathway. | Melody Debenham |
| 9/30/2014 | Potentially Responsible Party/State Interest Letter | Potentially responsible party letter sent to the National Park Service. | Melody Debenham |
| 2/14/2017 | Exposure Tracking Model Ranking | A new updated ranking with ETM has been completed for source area 78620 Building 27 AST. | Melody Debenham |
| 8/31/2017 | Institutional Control Record Established | Institutional Controls established and entered into the database. | Gretchen Caudill |
| 8/31/2017 | Cleanup Complete Determination Issued | Gretchen Caudill | |
| 5/30/2018 | Institutional Control Compliance Review | IC compliance review conducted. Staff changed from Gretchen Caudill to IC Unit. Closure/IC Details updated to reflect the 2017 Decision Document. Reminder system set to follow-up every five years. | Kristin Thompson |
| 2/1/2021 | Institutional Control Compliance Review | IC compliance review conducted. The landowner remains the NPS. A letter to the landowner was not issued at this time. | Evonne Reese |
Contaminant Information
| Name | Level Description | Media | Comments |
|---|---|---|---|
| BTEX | > Human Health/Ingestion/Inhalation | Soil | Excavation at the AST location between Building 27 and 28 detected a maximum concentration of ethlybenzene at 0.35 mg/kg and xylenes at 3.9-2.8 mg/kg at the vertical extent of excavation. |
| DRO | Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation | Soil | Excavation at the AST location between Building 27 and 28 detected a maximum concentration of 14,000 mg/kg and 7,9000 mg/kg at the vertical extent of excavation. |
Control Type
| Type | Details |
|---|---|
| Federal or State Agency GIS Database Note | Identification of the location of remaining soil and groundwater contamination on the NPS GIS database and use of the internal NPS planning process for all projects that directs the user to the GIS database to determine if contamination is present within the project area. |
Requirements
| Description | Details |
|---|---|
| Advance approval required to transport soil or groundwater off-site. | Standard condition. |
| 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) | Standard condition. |
| Excavation / Soil Movement Restrictions | A requirement that proper field screening and characterization be conducted during any soil excavation, digging, or trenching in the areas where residual soil contamination exists and that any contaminated soil encountered be managed in accordance with regulations applicable at that time. |
| Groundwater Use Restrictions | A restriction on installing groundwater wells or using groundwater from the site without prior DEC approval. |
| Other | Standard condition. |
| Periodic Review | ADEC will conduct a review of site conditions every three years. |
No associated sites were found.