Site Report: Dutch Hbr-Mt. Ballyhoo Transformer Vaults
| Site Name: | Dutch Hbr-Mt. Ballyhoo Transformer Vaults |
|---|---|
| Address: | Mt. Ballyhoo; Amaknak Island, Unalaska, AK 99685 |
| File Number: | 2542.38.014 |
| Hazard ID: | 25714 |
| Status: | Active |
| Staff: | Sarah Bernhardt, 9072697527 sarah.bernhardt@alaska.gov |
| Latitude: | 53.923167 |
| Longitude: | -166.515632 |
| 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
Four transformer bodies were identified in three below ground concrete vaults in 1998. The transformers were removed and disposed offsite in 2000. Soil from within the vaults were sampled for PCBs, DRO, and RRO. All three vaults (near Buildings A, B, and C) contained PCBs above cleanup levels. DRO was detected in vaults near Building A (380-2,320 mg/kg) and Building B (66,300 mg/kg DRO), and RRO was detected at Building B at a concentration of 89,400 mg/kg. Soil was removed from all vaults in 2001, however soil remained in Vault C because of a drain/sump that opened to the ground below the vault. Samples were taken in the Vault C drain and downgradient of all vaults, and analyzed for PCBs (4 samples downgradient from Building B were also analyzed for DRO). PCBs were detected at a concentration of 0.5 mg/kg in the Vault C sump, however analytes were not detected in any other samples. Grates were installed on the vault entries to prevent entry. In February 2019 a work plan was submitted for additional characterization to be conducted on behalf of the Qawalangin Tribe of Unalaska under the Native American Lands Environmental Mitigation Program (NALEMP). That work will be tracked under associated Hazard ID 27025, File No. 2542.38.035, "Dutch Hbr-Mt. Ballyhoo Fort Schwatka Transformer Vaults NALEMP."
Action Information
| Action Date | Action | Description | DEC Staff |
|---|---|---|---|
| 10/12/2003 | CERCLA SI | The 2001/2002 Islandwide SI/RI/IRA Report was received. The report documents the work completed during the 2001 and 2002 field seasons at various sites throughout Amaknak and Unalaska. The transformer vaults associated with Buildings A, B, and C were dry decontaminated in 2001 and the accumulated soil was shoveled from the vaults. Excavated soil was disposed of offsite and grates were screwed onto the top of each vault to prevent entry. Hand augers were advanced adjacent to each vault and samples were collected at depths equal to the bottom of the vaults or up to two feet below the vaults. One sample was collected within Building C vault and samples were collected downgradient of the Building B UST to determine if contamination was migrating. Samples were analyzed for DRo and PCBs. The sample within the vault did not exceed regulatory levels for PCBs, and downgradient samples were non-detect for PCBs. DRO was below action levels for all samples. The site is recommended for no further action as all samples were either non detect or below the Method 2 cleanup levels. | Meghan Dooley |
| 9/8/2011 | Site Added to Database | A new site has been added to the database | Mitzi Read |
| 9/12/2011 | Exposure Tracking Model Ranking | Initial ranking with ETM completed for source area id: 79153 name: Transformer Vaults | Meghan Dooley |
| 3/7/2019 | Document, Report, or Work plan Review - other | On March 6, 2019 ADEC received a draft work plan for "Fort Schwatka (Site 4), Draft Transformer Vault Characterization Work Plan" report from Ounalashka Corporation. | Rachael Petraeus |
| 3/12/2024 | Document, Report, or Work plan Review - other | DEC reviewed the Draft Final Mt. Ballyhoo Recreation and Postal Exchange (Rec-px) Transformer Vault Removal Action and Characterization / Battery And Stand-alone Transformer Site Investigation Report Unalaska, Alaska, dated February 2024. The report describes the investigation activities conducted during the spring of 2023 at the Recreation and Postal Exchange (Rec-PX) Transformer Vault at Mt. Ballyhoo in Unalaska, Alaska. Surface soil samples were collected and analyzed for diesel range organics (DRO), lead, and polychlorinated biphenyls (PCBs). Lead was the only contaminant exceeding DEC’s most stringent cleanup levels. The report recommended the removal of existing lead contamination and further characterization of the subsurface near the transformer vault. DEC recommends that an additional analytical sample be collected, directly north of the existing lead exceedance, concurrent with the planned removal action, to ensure adequate delineation of lead in all cardinal directions. | Ginna Quesada |
Contaminant Information
| Name | Level Description | Media | Comments |
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Control Type
| Type | Details |
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Requirements
| Description | Details |
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| Hazard ID | Site Name | File Number |
|---|---|---|
| 27025 | Dutch Hbr-Mt. Ballyhoo Fort Schwatka Transformer Vaults NALEMP | 2542.38.035 |