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Site Report: ARRC Knik Arm Power Plant

Site Name: ARRC Knik Arm Power Plant
Address: 229 Whitney Road, Adjacent to Railroad Yard, Anchorage, AK 99501
File Number: 2100.38.103
Hazard ID: 2995
Status: Active
Staff: Grant Lidren, 9072698685
Latitude: 61.224621
Longitude: -149.878966
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.


In 1998, 2,400 gallons of transformer oil containing PCBs was released from two electrical transformers at the Knik Arm Power Plant (KAPP). Response efforts contained the spilled oil in the area's storm water drain system, but some reached Ship Creek below the dam. It was estimated that approximately 1,900-2,100 gallons of product was recovered. Contaminated soil under the transformers was removed,treated to DRO levels 1,000 mg/kg or less, and returned to the excavation. In 2002, ADEC determined that no further remedial action (NFRAP) was required at the site in regards to the 1998 transformer spill, but indicated that further evaluation of DRO contamination at the site may be necessary. Sediment sampling of the KAPP pond in 1998 and 2005 indicate detectable levels of PAHs, VOCs, and PCBs, which are associated with the Power Plant. Administrative order on consent (US EPA Docket No. CERCLA 10-2004-0065) signed on 6/29/04 to include ARRC terminal and leased properties.

Action Information

Action Date Action Description DEC Staff
4/17/1998 Update or Other Action Hobbs Industries reports release of transformer oil from two electrical transformers at the Old Knik Arm Power Plant site. PERP served as the primary responder to this release of an estimated 2400 gallons of transformer oil in the substation area. Jim Frechione
5/14/1998 Update or Other Action Hobbs Industries indicates response efforts were to intercept product in the storm water drain system (Manholes B6 and B2) and excavate contaminated soil and stored on site. Jim Frechione
8/27/1998 Site Characterization Workplan Approved ADEC approves of Hobbs Industries work plan conditional on comments in Frechione letter. Jim Frechione
9/24/1998 Update or Other Action ADEC approves of site activity involving the removal of transformers from the spill location and excavation of additional soil. Hobbs Industries was also requested to define the nature and extent of soil and groundwater impacts resulting from the spill. Jim Frechione
10/19/1998 Update or Other Action Hobbs Industries reports that transformers were relocated and drained of remaining oil. They estimate approximately 2000 gallons of oil was recovered from the spill incident. They removed concrete ductwork in the substation area and excavated visible contaminated soil. Jim Frechione
11/16/1998 Update or Other Action ADEC sent memorandum to Attorney General's office to initiate cost recovery efforts. Jim Frechione
11/20/1998 Update or Other Action ADEC letter to Hobbs Industries commenting on results of soil stockpile samples (7600 to 13300 mg/kg DRO; 0.2 to 0.45mg/kg PCB) and proposal to thermally treat or soil wash. Hobbs Ind. was informed that any plan to treat soil and characterize the spill area requires an ADEC approved work plan. Jim Frechione
6/17/1999 Report or Workplan Review - Other On this date, ADEC received Ship Creek Brownfields Site Assessment Report Ship Creek Brownfields Site, dated May 1999, submitted by E & E. A site inspection identified numerous potential areas of contamination where samples of: soil; sediment; surface water; and/or groundwater were collected. These areas include: the dismantled electrical substation where the leaky transformers and oil spills have occurred; the former electrical substation where transformer leaks may have occurred; the former coal storage location; the boiler ash silo area; the former dry well location where waste liquids from KAPP equipment and batteries may have been disposed of; the loading and unloading areas; The cooling pond where unregulated (i.e. not permitted by the NPDES program) floor drain discharges may have occurred and contaminants may have migrated from the electrical substation; Ship Creek above the dam where the cooling pond overflow could have impacted; and Ship Creek below the dam where unregulated floor and storm drain discharges have occurred. Area wide soil samples collected contained DRO above ADEC migration to groundwater cleanup levels at four locations: the dismantled electrical substation with DRO up to 414 mg/kg at 4 to 8 feet bgs, the coal storage area with DRO up to 2,100 mg/kg at 1 foot bgs, the former electrical substation with DRO up to 1,010 mg/kg at 9 to 11 feet bgs, and the loading area with DRO up to 297 mg/kg at 0 to 0.5 feet bgs and benzene up to 0.08 mg/kg at 0 to 0.5 feet bgs. PCBs of 0.057 mg/kg were detected in the surface soil at the dismantled electrical which is well below ADEC cleanup levels. PCBs were not detected in the subsurface soil at the KAPP facility. At the three MWs, ground water samples collected contained DRO, with the highest reading from the MW adjacent to the dismantled electrical substation with DRO up to 19.0 mg/L. Off site migration from the KAPP facility is evident by elevations of metals, DRO and PCBs in downgradient areas such as Ship Creek. This is attributed to cooling pond and KAPP storm drain discharge locations which most likely contributed to contaminants above background cleanup levels. Grant Lidren
9/17/1999 Update or Other Action Site characterization work plan was submitted by T&R Environmental Consulting. The plan was to investigate the spill site and characterize the nature and extent of contamination remaining from the transformer spill incident. Jim Frechione
9/23/1999 Update or Other Action ADEC conditionally approves of T&R workplan. Jim Frechione
1/27/2000 Meeting or Teleconference Held A meeting between governmental agencies was held to discuss the possible re-use of the Old Knik Arm Power Plant for power generation. The entity proposing this action is Marlow Power and Steam, Inc. represented by Steigers Corp. Jim Frechione
10/23/2000 Update or Other Action T&R Environmental Consulting submit stockpile soil samples and the need to treat to target cleanup levels. T&R also submitted a site characterization plan for the spill site. Jim Frechione
10/26/2000 Site Ranked Using the AHRM Initial ranking. Upon entry, the DB Administrator changed the Toxicity Value from 1.5 (invalid value) to 1 (Transformer Oil); GW Exposure Index Value from 0.4 to 0 because if SW is not a DW source then there is no potential for exposure; and Environmental Recreation Value from 2 to 0 because the site is not actually located in a designated environmentally designated area. Priority changed from Medium to Low. Jim Frechione
10/27/2000 Site Added to Database Transformer oil release. Jim Frechione
11/17/2000 Update or Other Action ADEC responds to T&R investigation and recognized that they did not identify soil contamination in the substation spill area. However, EPA's report did identify areas of soil and groundwater contamination in the substation area that may (or may not) be the result of the 1998 spill. ADEC concluded no further investigative action at the time was required but future action might be necessary if levels posed a risk. The soil stockpile treatment plan of soil washing was still being evaluated. Jim Frechione
1/12/2001 Update or Other Action Hobbs Industries submit a work plan to treat the soil stock pile by soil washing. Jim Frechione
1/22/2001 Update or Other Action ADEC approves of the soil washing subject to conditions listed in letter to Hobbs. Jim Frechione
1/31/2001 Update or Other Action Hobbs' consultant (T&R Consulting) submit revised work plan. Jim Frechione
2/5/2001 Cleanup Plan Approved ADEC approves revised work plan. Jim Frechione
2/7/2001 Update or Other Action Hobbs Industries indicates that they were able to re-locate soil stockpile (60 cubic yards) into power house building for washing. They requested 1000 ppm DRO for landspread purposes within substation area. Jim Frechione
7/26/2002 Update or Other Action ADEC requests status of soil washing operation and impacted soil. Jim Frechione
7/27/2002 Update or Other Action Hobbs Industries provides information that soil washing was completed in 2001. Soil samples confirmed soil was below the 1000 ppm DRO level approved for placement in former substation area. Jim Frechione
10/15/2002 Update or Other Action No Further Remedial Action letter for the 1998 transformer spill was issued. However, this determination did not apply to the entire site and it should be recognized there may be elevated levels of hazardous substances from other spill events. Jim Frechione
6/21/2007 Update or Other Action Remedial Investigation ARRC Anchorage Terminal Reserve U.S. EPA Docket No. CERCLA 10-2004-0065, submitted by ENSR and recieved by the ADEC on this date. This site is located at the north bank source area SE-1 in the Anchorage Terminal Reserve lease property 120. SE-1 encompasses contaminated sediment in the KAPP pond. Sediment samples in the KAPP pond indicate PAHs and PCBs in moderate concentrations. Some low level exceedances of inorganics are also present. For more information consult CS file # 2100.38.447 ARRC Anchorage Terminal Reserve Grant Lidren
4/10/2008 Exposure Tracking Model Ranking Initial ranking with ETM completed. Grant Lidren

Contaminant Information

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