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Site Report: Hilcorp NS Building U-21 (BPX)

Site Name: Hilcorp NS Building U-21 (BPX)
Address: Main Construction Camp, Eastern Operating Area, Prudhoe Bay, AK 99734
File Number: 300.38.218
Hazard ID: 3258
Status: Cleanup Complete - Institutional Controls
Staff: Andrea Carlson, 9074515174 andrea.carlson@alaska.gov
Latitude: 70.254805
Longitude: -148.380440
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

Building used to store heavy equipment. During routine maintenance in 1997, hydrocarbon contamination was found in a trench excavated outside the NE corner of Building U-21. In 1997, the following concentrations were reported from a soil pad sample: 5030 ppm DRO; 1610 ppm RRO; 10.4 BTEX. During a 1998 site investigation, three MW were installed and off-pad surface water samples were collected. Resuts showed no violations of AK Water Quality standards. However, the extent of the contamination had not been identified. Subsequent investigations conducted to accomplish this. See Actions. Previous PM was Sundet.

Action Information

Action Date Action Description DEC Staff
8/31/1999 Update or Other Action Site Characterization Report dated February 1999 received by DEC. Linda Nuechterlein
9/20/1999 Update or Other Action Site Closure Plan dated August 1999 received. Linda Nuechterlein
5/11/2000 Update or Other Action 1999 Report of Findings received dated March 2000. Linda Nuechterlein
6/17/2003 Update or Other Action 2002 Site Monitoring Report by ENSR dated May 19, 2003 presented results of pore water and surface water sampling for 2002. Pore water and surface water samples were not collected during 2001. Linda Nuechterlein
5/20/2004 Update or Other Action 2003 Site Monitoring Report by Oasis dated March 26, 2004 presented results of pore water and surface water sampling for 2003. Linda Nuechterlein
6/22/2004 Update or Other Action Sheening off pad discovered during a site visit on this date. Linda Nuechterlein
8/18/2004 Proposed Plan Site characterization plan dated 7/20/04 proposed additional investiation and monitoring activities for 2004 as follows: sample/field screen up to six new boreholes; sample up to four surface water samples and three MWs; and prepare report. Linda Nuechterlein
8/19/2004 Site Added to Database DRO contamination discovered in 1997. However, site never entered into CS database. Sarah Cunningham
3/17/2005 Update or Other Action 2004 Site Assessment and Annual Monitoring Report Building U-21 Site, Prudoe Bay Unit submitted by Oasis, dated December 14, 2004 , and recieved by the DEC on this date. Active layer MW01 indicate DRO and GRO above cleanup levels. Surface water samples SW03 & SW04 located at the "toe" of the pad also contaminated with DRO and GRO above ADEC cleanup levels. Grant Lidren
5/11/2005 Cleanup Plan Approved CAP approved and transportation and storage of restricted-use gravel (between 200 – 2000 mg/kg DRO) to Prudhoe Bay Unit W Pad is approved; Transportation and treatment of contaminated material either by landfarming at East Dock or thermal treatment at Alaska Interstate Construction (AIC) is approved. Linda Nuechterlein
7/27/2005 Site Number Identifier Changed Changed Workplan from 10 to 01. Former Staff
6/21/2006 Update or Other Action Recieved 2005 Corrective Action Report for Building U-21. 130 cubic yards of petroleum contaminated gravel were excavated from one of two impacted areas near the NE corner of Building U-21. Excavation did not remove impacted gravel adjacent to a buried gas line, or northeast of the buiding, leaving gravel in place containing DRO up to 5,180 mg/kg. Additional stained, fugitive gravel removed from beneath organic layer at toe of pad. Confirmation sample from the bottom of the excavation had DRO at 176 mg/kg. Report recommends continued surface water monitoring. Bill O'Connell
6/21/2006 Site Characterization Report Approved Recieved 2005 Annual Water Monitoring Report. Porewater samples collected from MW02 and MW03 and three surface water samples collected from monitoring points SW01, SW02, and new monitoring location SW05. MW02 contained benzene at 0.00224 mg/l, no other analytes were detected in MW02 or MW03. DRO was detected in surface water at SW05 at 0.726 mg/l. Report recommends continued monitoring. Bill O'Connell
3/21/2007 Exposure Tracking Model Ranking Bill O'Connell
1/3/2008 GIS Position Updated Position updated with Contaminated sites GIS Grant Lidren
7/13/2009 Document, Report, or Work plan Review - other Reviewed 2009 Work Plan. Visual observation and sheen testing will be conducted at the site to see if off-pad transport is occurring. Bill O'Connell
9/10/2009 Site Visit Site visit on 9/1/09. No sheen was visible on surface water adjacent to the site, Bill O'Connell
4/19/2010 Exposure Tracking Model Ranking A new updated ranking with ETM has been completed for source area 74233 AST in NE Corner of Bldg U-21. Bill O'Connell
5/27/2010 Cleanup Complete Determination Issued The Alaska Department of Environmental Conservation, Contaminated Sites Program (ADEC) has completed a review of the environmental records associated with BPX Building U-21, located in Prudhoe Bay, Alaska. Based on the information provided to date, it has been 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 (ICs). Bill O'Connell
5/27/2010 Institutional Control Record Established Institutional Controls established and entered into the database. Bill O'Connell
2/1/2011 Document, Report, or Work plan Review - other Reviewed 2009 Visual Monitoring Report. Surface water in the area of concern was inspected for hydrocarbon sheen; none was present. Bill O'Connell
5/30/2012 Institutional Control Compliance Review IC review conducted and reminder system set-up for 2015 follow-up with responsible party. Project manager changed from Bill O'Connell to IC Unit. Kristin Thompson
5/10/2013 Update or Other Action Site manager changed from IC Unit to Bill O'Connell in order update the site record. Evonne Reese
5/10/2013 Update or Other Action A discrete area of hydrocarbon contamination in soil was noted east of Building U-21 during trenching for gas line installation in 2012. Bill O'Connell
5/28/2015 Institutional Control Update An IC reminder letter was issued to the responsible party on this date. Kristin Thompson
6/4/2015 Institutional Control Update Received a confirmation letter from the responsible party verifying that there have been no changes in land use on this property. Evonne Reese
6/9/2020 Institutional Control Compliance Review Received an email report confirming that land use has not changed for this property. The next compliance review will be conducted in 5 years time. Evonne Reese
3/19/2024 Institutional Control Update DNR-SAIL added as affiliate (Office of Primary Responsibility). For DNR LAS information: ADL# 420764 Jennifer McGrath

Contaminant Information

Name Level Description Media Comments
DRO > Method 1 (Arctic only) Soil

Control Type

Type Details
Signed CS Determination

Requirements

Description Details
Advance approval required to transport soil or groundwater off-site.
When Contaminated Soil is Accessible, Remediation Should Occur

No associated sites were found.

Missing Location Data

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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