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Site Report: Alyeska PS 05 20RB0 Valve Release


Site Name: Alyeska PS 05 20RB0 Valve Release
Address: MP 137 Dalton Highway, Pipeline MP 274.7, Coldfoot, AK 99701
File Number: 330.38.098
Hazard ID: 3852
Status: Cleanup Complete - Institutional Controls
Staff: IC Unit, 9074655229 dec.icunit@alaska.gov
Latitude: 66.812814
Longitude: -150.665844
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

On September 22, 2001, 2,037-gallon of crude oil was released at PS05 Manifold Building from a valve designated as 20RB0 when power was shut down and restored as part of routine operations. To protect workers and structures, approximately 12,000 gallons of water mixed with 3% Aqueous Film Forming Foam (AFFF) was released into the Manifold Building to control the explosive atmosphere. AFFF and up to 200 gallons of crude escaped the building through the eastern and western doors and between the concrete floor and metal wall flashings along the building's southern wing. Excavations during the initial response removed contaminated soil near the eastern and western doorways, and confirmation sampling showed that contaminant residue was below ADEC cleanup levels (CUL). Excavations along the southern perimeter removed impacted soil to the extent practical without jeopardizing the integrity of the building footers, but Benzene and DRO were left in place. Before backfilling, a corrugated metal sump (called Sump B) was installed, and a VES was installed in the trench along the southern side of the Manifold Building and operated between 2003 and 2006. Free-phase product has been noted in Sump B (most likely in 2003, but the date is unconfirmed). Alyeska spill number 2001077 was assigned to this site. Prevention and Emergency Response Program (PERP) Spill Number 01309926501. PERP File Number is 330.02.167.

Action Information

Action Date Action Description DEC Staff
2/12/2002 Update or Other Action Receipt of Contamination Assessment 20RB0 Valve Crude Release Alyeska Spill Number 2001077 Trans Alaska Pipeline System Pump Station 5 report submitted by SLR, dated December 2001. Excavation was performed around the Manifold building perimeter to the extent practicable. Following cleanup efforts, soil samples were taken around the building perimeter and further away from the building in the yard area. Only samples from around the building perimeter exceeded the arctic zone criteria for GRO, benzene, and xylenes with concentrations up to 2,540, 20.3, and 135.8 mg/kg, respectively at depths of 2-4 ft. Slotted PVC pipe was laid horizontally in the excavation trench around the building perimeter to facilitate future remediation. Grant Lidren
3/14/2002 Site Added to Database Site involves crude oil contamination. Site transferred from PERP. Deborah Williams
3/14/2002 Site Ranked Using the AHRM Preliminary ranking. Deborah Williams
4/9/2003 Update or Other Action Receipt of SLR's 2002 PS 05 Site Assessment Report, dated March 2003. Additional site assessment including borings, test pits, and monitoring well installation (initially to determine gradient of suprapermafrost groundwater). Soil was described as concrete-like and frozen but not ice-rich. Soil samples did not exceed Method Two cleanup levels for either arctic or 40" zone. Water samples exceed Table C levels for GRO, DRO, and bezene at 3.01, 50.2, and 2.25 mg/L respectively. Grant Lidren
3/30/2004 Update or Other Action ADEC received SLR's report on 2003 PS 5 Soil Vapor Extraction Unit Installation and Water Monitoring Report for this site. The SVE operated from September 19 through October 8, 2003. The system removed 46.1 pounds of VOCs from perimeter soil of the Manifold Building, including 0.0775 pounds of benzene. Contaminant levels were found in the suprapermafrost groundwater up to 3.87 ppm benzene, 10.4 ppm GRO, and 11.5 ppm DRO. SLR states that the concentrations appear to be decreasing. Based on the data obtained during the site investigations of 2002 and 2003, suprapermafrost groundwater appears to migrate preferentially along the building perimeters and pipe trenches, or other non-frost susceptible soil. There is no evidence that contaminated water is migrating off the Pump Station pad. Deborah Williams
3/3/2005 Update or Other Action ADEC received SLR's report on 2004 PS5 Water Monitoring and Remedial Action Report. According to the report, the SVE unit operated from early June through October 15, 2004. During that time, the SVE unit removed approximately 492.4 pounds of petroleum hydrocarbons from the soil adjacent to the Manifold Building, including 0.98 pounds of benzene. Total weight removal to date is 538.5 pounds of total petroleum hydrocarbons. The results from the suprapermafrost groundwater monitoring wells show hydrocarbons in excess of the ADEC water quality criteria still exist around the vicinity fo the Manifold building. MW 03-08 which is near the source area had benzene level at 2.19 mg/L, GRO level at 7.19 mg/L, and DRO level at 9.94 mg/L. Deborah Williams
2/6/2006 Update or Other Action ADEC received the 2005 Groundwater Monitoring and Remedial Action Report for the PS5 Manifold Building site. According to the report, the 2005 season removed approximately 18.9 pounds of hydrocarbons. The total mass removal of petroleum hydrocarbons to date is 557.4 pounds. There was a substantial decrease of hydrocarbon removal from 2004 to 2005. Although the decrease is at least partially the result of high water levels during 2005, the levels suggest that much of the crude in soil has been volatilized and that the benzene level in soil may now be below the RCRA haz waste characteristic concentration. SLR recommends that the SVE system be operated during the 2006 field season to verify the low recovery. The highest concentrations of petroleum compounds in suprapermafrost water continue to be found at monitoring well MW03-08, with GRO, DRO, RRO, and benzene concentrations remaining above ADEC cleanup levels. All other monitoring wells show petroleum hydrocarbons below ADEC cleanup levels with the exception of RRO in Sump B. Deborah Williams
2/16/2007 Update or Other Action ADEC received SLR's report on the 2006 Water Monitoring and Remedial Action Report for PS 5. According to the report, the SVE unit operated from August 28 through October 10, 2006. During that time approximately 9.4 pounds of hydrocarbons were removed from the ground adjacent to the Manifold Building via SVE. To date, the approximate total mass removal of petroleum hydrocarbons is 567 pounds. Evaluation of the 2004, 2005, and 2006 SVE exhaust gas results suggests that the magnitude of VOC contamination in the soil has been significantly reduced through SVE treatment. Based on recovery data and soil sample analytical results, SLR recommends that operation of the SVE system be terminated. SLR recommends that groundwater monitoring continue in 2007, as the monitoring well MW03-08 continues to have hydrocarbon concentrations above ADEC cleanup levels. Deborah Williams
3/2/2007 Exposure Tracking Model Ranking Initial ranking complete. Deborah Williams
3/16/2007 Update or Other Action Date of letter approving termination of SVE operation based on contamination remaining not effectively treated by this system (heavier petroleum). Deborah Williams
3/7/2008 Update or Other Action Received Pump Station 5 2007 Water Monitoring and Remedial Action Report. Groundwater concentrations below Table C in all wells with the exception of 0.0476 mg/L benzene, 1.70 mg/L GRO, 7.15 mg/L DRO, and 1.62 mg/L RRO in MW 03-08 which is in the source area. SLR recommends continued monitoring at all six wells sampled in 2007. Figure 3 indicates that the local groundwater gradient is to the west but is a very low gradient of ~0.01. Review of report included laboratory review checklist. Keather McLoone
6/10/2008 Update or Other Action Approved Pump Station 5 Manifold Building 2008 Groundwater Monitoring Work Plan received 5/30/08. Keather McLoone
2/13/2009 Update or Other Action Receipt of Pump Station 5 2008 Ground Water Monitoring Report. Five wells and a sump sampled with one well (MW03-8) containing DRO, RRO, and benzene above Table C. This well was sampled in duplicate and duplicate results confirm primary. Also, this well is near the site source area. While DRO and RRO results were consistent with historical levels (with steady or declining trend), the benzene concentrations showing a declining trend with 2008 results 2 orders of magnitude less than 2003 benzene results. Plan is to continue monitoring in 2009. Report review included laboratory review checklist. No trip blank accompanied the shipment which means the BTEX results could not be evaluated for potential "trip" contamination. Keather McLoone
5/22/2009 Report or Workplan Review - Other Review of Pump Station 5 Manifold Building 2009 Ground Water Monitoring Work Plan. A single groundwater monitoring event is planned for late July or August. Suprapermafrost ground water samples will be collected from six wells: MW02-01, MW02-03, MW02-04, MW02-06, MW03-08, and Sump B. Analyses will BTEX, GRO, PAH, and DRO/RRO. Keather McLoone
4/20/2010 Report or Workplan Review - Other Review of Pump Station 5 Manifold Building 2009 Groundwater Monitoring Report received 4/1/10 from SLR on behalf of Alyeska. Only 2 of the 6 wells contained enough water to be sampled during 2009. MW-03-08 contained benzene, DRO and RRO above Table C (duplicate sample result only above for DRO). The overall trend for these constituents in this well is stable or decreasing. Current and historical data suggest that the contaminant plume is limited to the source area, in the vicinity of this well. Alyeska is proposing to do another round of sampling and then propose a conditional closure for this site, unless results show a different trend. SLR proposes sampling next year in later July or early August when groundwater levels have historically been higher. Keather McLoone
5/24/2010 Report or Workplan Review - Other Review of Pump Station 5 Manifold Building 2010 Groundwater Monitoring Workplan. A single surprapermafrost groundwater sampling event is planned for 2010 Keather McLoone
2/22/2011 Report or Workplan Review - Other Review of Pump Station 5 Manifold Building 2010 Groundwater Monitoring Report. DRO and RRO exceeded in MW-03-08 at 3.20 and 1.12 mg/L respectively. Duplicate results were 8.30 mg/L DRO and 3.20 mg/L RRO. Samples were collected in late September and only 2 of 6 wells had sufficient water volume for sample collection. Keather McLoone
6/9/2011 Report or Workplan Review - Other Date of receipt of Pump Station 5 Manifold Building 2011 Groundwater Monitoring Workplan. Alyeska plans to conduct a single suprapermafrost groundwater sampling event. DEC approval conditional upon an attempt be made to sample in summer, the earlier the better chance of finding wells not dry. Keather McLoone
3/23/2012 Report or Workplan Review - Other Date of receipt of 2011 Groundwater Monitoring Report. Groundwater gradient not indicated on site figure. Six wells sampled and two had constituents above Table C. DRO, benzene, and RRO in MW-03-08 and DRO in MW-02-03. GRO/BTEX data for Sump B location not collected due to broken containers. Without groundwater gradient information it is difficult to tell if this plume is currently bounded but would appear to not be. Need to consider this when reviewing next workplan document. Keather McLoone
5/11/2012 Report or Workplan Review - Other Date of receipt of Pump Station 5 Manifold Building 2012 Groundwater Monitoring Workplan. Alyeska plans to conduct a single suprapermafrost groundwater sampling event. DEC approval conditional upon an attempt be made to sample in summer, the earlier the better chance of finding wells not dry. Sampling is planned for July. Keather McLoone
2/5/2013 Update or Other Action Updated coordinates based on 2012 work report and Google Earth imagery. Richard Bernhardt
2/6/2013 Report or Workplan Review - Other Reviewed the 2012 Work Report. Six monitoring wells were sampled, and only one (MW-03-08) had detectable analyte concentrations. This well also had exceedances for benzene, DRO, and RRO at 0.0169, 7.66, and 1.92 ppm, respectively. With one exception (MW-02-03 exceeded DRO Table C by 0.05 ppm in 2011) none of the other samples or wells have exceeded ADEC CUL within the past nine years. Alyeska requested site closure and well decommissioning. Vapor intrusion is the greatest concern at this site, and benzene concentration and depth are right at the margins of of VI target levels. Richard Bernhardt
2/7/2013 Exposure Tracking Model Ranking A new updated ETM ranking has been completed for source area 74827 Crude Oil Release based on a comprehensive review of all work reports to date. All exposure pathways are now either "Pathway Incomplete" or "De Minimis Exposure." Richard Bernhardt
2/21/2013 Cleanup Complete Determination Issued By law, DEC is required to recover expenses incurred during cleanup, including staff oversight time. Current and former landowners may be liable for state cleanup expenditures. Alyeska's remediation efforts have removed contamination to the maximum extent practical until the manifold building is eventually dismantled. At that time, Alyeska will characterize sub-structure soil within one year of the building being dismantled. Any contamination above cleanup levels will also have to be excavated and remediated within one year of dismantlement. Remaining contaminant concentrations do not pose an unacceptable risk. Finally, Alyeska will report the status of the manifold building to ADEC at five year intervals, or sooner if the building is dismantled beforehand. Richard Bernhardt
2/22/2013 Institutional Control Record Established Institutional Controls established and entered into the database. Richard Bernhardt
5/6/2013 Update or Other Action On this date, ADEC recieved a signed CC-IC document from Alyeska. Grant Lidren
5/22/2013 Report or Workplan Review - Other Received and approved a work plan to decommission all remaining monitoring wells at this site per terms of the 2013 CC-IC ROD. It is noteworthy that MWs 02-02, 02-05, 02-07, and 03-09 have not been located in over 7 years and will only be decommissioned if they can be located in 2013. Richard Bernhardt
1/2/2014 Update or Other Action On this date, ADEC received the 2013 Well Decommissioning Report PS 5 Manifold Building submitted by SLR dated December 2013. SLR decommissioned monitoring wells 02-01, 02-02, 02-03, 02-04, 02-05, 02-06, 02-07, and 03-08. MW-03-09 could not be located. Grant Lidren
11/27/2015 Institutional Control Compliance Review IC compliance review conducted and staff name changed from Lidren to IC Unit. Reminder system in place to review functional status of manifold building in February 2018. Nathan Maxwell
4/10/2017 Update or Other Action PFOS and PFOA are a potential CoC due to the use of aqueous fire fighting foam (AFFF). PFOS and PFOA have been added as a CoC to this site for tracking purposes. These contaminants will need to be evaluated when it is accessible in accordance with the institutional controls already established for this site. Grant Lidren

Contaminant Information

Name Level Description Media Comments
Benzene > Table C Groundwater Benzene concentration in MW-03-08 was 0.0169mg/L in 2012. Higher concentrations probably remain beneath the southern edge of the manifold building.
DRO > Table C Groundwater DRO concentration in MW-03-08 was 7.66mg/L in 2012. Higher concentrations probably remain beneath the southern edge of the manifold building.
RRO > Table C Groundwater RRO concentration in MW-03-08 was 1.92mg/L in 2012. Higher concentrations probably remain beneath the southern edge of the manifold building.

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 Crude oil probably remains beneath the manifold building, but excavation beneath the foundation was impractical. Soil beneath the building needs to be characterized within one year of building dismantlement. If concentrations exceed ADEC cleanup levels, it will also be excavated and remediated within one year of building dismantlement.
Other Report the status of the manifold building every five years, or sooner if the building is dismantled beforehand.
Other Record of contamination kept in the Alyeska MAC database.

Missing Location Data

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