Superfund is the federal program designed to clean up contaminated sites. It was created by Congress in 1980 and is formally termed the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA).
This law provides broad federal authority to respond directly to releases or threatened releases of hazardous substances that may endanger public health or the environment.
The law authorizes two kinds of response actions:
- Removal actions, where actions may be taken to address releases or threatened releases requiring prompt response;
- Remedial actions, designed to provide long-term protection to human health and the environment from hazardous substance releases. Remedial actions can be conducted only at sites listed on EPA’s National Priorities List (NPL).
On August 30, 1990, EPA listed the Eastern Michaud Superfund Site (EMF Site) on the CERCLA National Priorities List. The EMF Site consists of the FMC facility, the adjacent J.R. Simplot Company fertilizer plant, and the surrounding area that may have been affected by plant operations.
CURRENT STATUS: Remedial Design and Remedial Action for the FMC OU
EPA issued the Interim Record of Decision Amendment (IRODA) in September 2012 for the FMC Operable Unit (OU) and a Unilateral Administrative Order (UAO) in June 2013 directing FMC to implement the remedy specified in the IRODA. Additional information on the CERCLA process that led to the IRODA and UAO is provided below in The Journey to the IRODA. As required by the UAO, FMC has been on an EPA-directed schedule to prepare detailed remedial designs and plans for the soil and ground water remedies. FMC prepared and submitted to EPA the first required document, the Remedial Design Work Plan (RDWP), in August 2013 and following revisions to address comments from EPA, IDEQ and the Tribes, EPA approved the RDWP in December 2013. The RDWP sets forth the planned division of the remediation of the site into two categories of work, the Soil Remedy and the Groundwater Remedy, and a preliminary schedule for completing the remedial design and commencing remedial action construction.
During 2013 and 2014, FMC performed various EPA-approved field studies to develop additional data to support the soil remedial design. In March 2014, FMC submitted to EPA the preliminary (30%) remedial design for the soil remedy which sequenced the soil remedy into the site-wide grading and capping phases. The site-wide grading phase of the soil remedy involves re-grading the site for surface water control and preparation for capping. FMC addressed comments from EPA, IDEQ and the Tribes on the preliminary design and Remedial Action Work Plan (RAWP), including a Dust Control and Air Monitoring Plan, for the site-wide grading phase of the soil remedial action. EPA approved these documents and FMC commenced construction in September 2014. As of May 2015, the site-wide grading phase is more than 50% complete and the capping phase construction is planned to begin during third-quarter 2015. The soil remedy is planned to be completed in late 2015 or early 2016.
Also during 2014, groundwater extraction zone performance testing was conducted to provide further information needed for detailed design of the groundwater extraction and treatment system. FMC submitted to EPA the preliminary (30%) remedial design for the groundwater remedy in January 2015 and will continue to work with EPA, IDEQ and the Tribes to address comments as the remedial design progresses through to the final design. The groundwater remedy is planned be constructed in 2016 and fully operational in 2017.
SUPERFUND PHASE 1: 1998 CERCLA Record of Decision (ROD)
Under the terms of a 1991 Administrative Order on Consent (AOC) with EPA, and in cooperation with IDEQ and the Shoshone-Bannock Tribes, FMC and Simplot conducted a Remedial Investigation/Feasibility Study (RI/FS) of the two facilities and surrounding area. Following completion of EMF RI/FS, EPA issued a CERCLA Record of Decision (ROD) in 1998 that addressed the entire EMF Site, including the FMC, Simplot and Off-Plant Subareas. Under the terms of the 1998 ROD, EPA selected cleanup actions for the FMC Plant Subarea, now referred to as the FMC Plant Operable Unit (OU).
IDEQ agreed with the selected remedies for all three of the EMF Subareas, including those for the FMC facility. However, EPA withdrew a consent decree negotiated with FMC under which FMC had agreed to implement the CERCLA remedial actions at its facility. The withdrawal was based on comments submitted by the Tribes. Without an entered consent decree to implement the 1998 ROD for the FMC Plant OU, FMC was unable to implement the cleanup remedies specified in the ROD.
SUPERFUND PHASE 2: 2012 Interim Record of Decision
FMC ceased production of elemental phosphorus at its Pocatello facility in December 2001. This led EPA and FMC to enter into another AOC in October, 2003 for a Supplemental Remedial Investigation and Feasibility Study (SRI/SFS) of the FMC Plant OU. This was driven primarily by EPA’s finding that additional investigations and evaluations were needed for the plant areas that had been actively operated at the time of the 1998 ROD, but where operations ceased with the 2001 plant shutdown.
The SRI/SFS was completed in July 2010 and EPA selected a remedy and held public meetings to get comments on their Proposed Clean Up Plan in the Fall of 2011. The EPA evaluated public comments, the largest number in support of the EPA plan, and issued a decision document in September 2012 – the Interim Record of Decision Amendment (IRODA). The proposed plan and the IRODA require the following clean up elements for the FMC Plant OU.
Soil Remedy Design and Construction Elements:
- Implementation of an FMC OU-wide storm water runoff management plan, including FMC OU-wide grading and the collection of storm water in retention basins.
- Placement of evapotraspirative (ET) caps over certain areas of the property where contaminants have the potential to migrate to groundwater.
- Placement of soil cover over certain areas of the property to prevent direct contact with fill materials and shield naturally occurring gamma radiation, including the slag pile.
- Implementation of a remedy management system to integrate the existing RCRA Pond caps with the development of new caps, access roads, groundwater extraction system and utility lines.
- Excavation of the upper six (6) inches of soil from the small parcel directly north of the old ore pile.
- Cleaning of the reinforced concrete underground storm water piping to remove potential residual P4 and soil/materials potentially containing metal and radiological constituents.
- Installation of additional engineering controls to further limit access as appropriate.
Soil Remedy Operation, Monitoring and Maintenance Elements:
- Implementation and monitoring of institutional controls to all or part of the site, as appropriate that prohibit activities that may disturb the remedies, including access controls and/or land use covenants or easements placing restrictions on property use (including groundwater use) restrictions, in addition to those institutional controls already in place.
- Implementation of a gas monitoring program at the FMC OU CERCLA capped ponds and subsurface areas where elemental phosphorus is present.
- Implementation of an operation and maintenance plan for the implemented remedial action.
Groundwater Remedy Design and Construction Elements:
- Installation of a groundwater extraction to provide hydraulic containment of the shallow aquifer. Treatment of the extracted groundwater will be by one of two options: A) discharge to the City of Pocatello POTW, or B) on-site treatment and discharge to an on-site percolation/evaporation basin(s).
Groundwater Remedy Operation, Monitoring and Maintenance Elements:
- Implementation of a long-term groundwater monitoring program to evaluate the effectiveness of the soil and groundwater remedial actions, based on the current Interim CERCLA groundwater monitoring program.
- Implementation of an operation and maintenance plan for the implemented remedial action.
The Journey to the IRODA
In 2009, FMC finalized and EPA approved the Final SRI Report and Final Groundwater Current Conditions Report, both of which completely detailed the extent of contamination in the soil and groundwater at the FMC Plant OU. Contaminants of Concern (COCs) included metals, radionuclides, elemental phosphorus (P4), and total phosphorus (in surface water from groundwater discharging to the Portneuf River). During the SRI, areas north, south, and west of the FMC Plant were also investigated for impacts from windblown contaminants. Collectively, these studies formed the basis for the Supplemental Feasibility Study (SFS) evaluations of soil and groundwater remedial alternatives at the FMC Plant OU. The design of the data collection studies, the actual collection of data, and the remedial alternatives studied fully engaged the resources of EPA, IDEQ, FMC and the Shoshone-Bannock Tribes.
In 2010, FMC completed the SFS Report, which examined cleanup alternatives to address the following:
- risks to potential future commercial or industrial workers at the site due to exposure to fill materials;
- risks to human health and the environment due to potential migration of COCs to groundwater; and
- the movement of COCs in groundwater discharging to the Portneuf River.
Despite the fact that the Northern Properties on the FMC Plant OU are zoned commercial and industrial and are deed restricted to prevent residential use, the SFS Report also examined risks to future/hypothetical residents living in those areas. This was done in response to concerns from the Shoshone-Bannock Tribes about potential residential exposures, despite the fact that residential use of the property is deed restricted and prohibited under the land use zoning.
During the SFS, Remediation Areas (RAs) were identified to group areas with similar characteristics that could be remediated using similar methods.
Multiple soil and groundwater remedial alternatives were evaluated in the SFS in accordance with the nine criteria specified in the NCP. Based on the SFS findings, EPA released a Proposed Plan for the FMC plant site in September 2010. The SFS evaluations of the soil and groundwater remedial alternatives are summarized below, followed by EPA’s preferred alternative. After EPA received public comment on the Proposed Plan, EPA developed an Interim ROD (IROD) that formally designated the remedial action to be conducted at the FMC Plant OU.
The alternatives for soil remediation identified in the SFS were evaluated in accordance with the nine criteria specified in the NCP. The soil alternatives and their comparative rankings of high, moderate, or low under each criterion are summarized here:
|Evaluation Criterion||Soil Alternative 1:
|Soil Alternative 2:
Core Elements (all), RIR (4 RAs), Gamma and ET Capping (10 RAs), Clean and Treat Offsite (1 RA)
|Soil Alternative 3:
Core Elements (all), Gamma and ET Capping (13 RAs), Excavate and Consolidate (1 RA), Clean and Treat Offsite (1 RA)
|Soil Alternative 4:
Core Elements (all), Gamma and ET Capping (10 RAs), Excavate and Consolidate (4 RAs), Clean and Treat Offsite (1 RA)
|Overall Protection of Human Health and the Environment||Low||Moderate to High||High||Moderate|
|Compliance with ARARs||Low||High||High||High|
|Long-Term Effectiveness and Permanence||Low||High||High||High|
|Reduction of Toxicity, Mobility, or Volume through Treatment||Low||Moderate||Moderate||Moderate|
|Short-Term Effectiveness||Low||Moderate to High||High||Moderate|
Annual O&M Cost
|Moderate to High
EPA’s Preferred and ultimately IRODA selected Alternative (Soil Alternative 3) incorporates several common/core remedial actions:
- institutional controls,
- stormwater management, and monitoring,
- Evapotranspiration (ET) and gamma caps.
Soil Alternative 3 – IROD Selected Remedial Action (click to enlarge)
This figure depicts the extent of the proposed remedial action under EPA’s selected soil remedial alternative 3.
At RAs B, C, D, E, H, and K: After grading, ET caps would be installed to reduce unacceptable risks to future site workers as well as migration of COCs to groundwater. In addition, ET caps also would be installed over RAs F1 and F2. Under this alternative, a gamma cap would also be installed over the entire slag pile (RA-F), and in RAs A, A1, and G to reduce risks of exposure to future site workers to gamma radiation and control site run-off.
At RA-J: Excavation and consolidation of soil would be required. RA-J was not used for plant production activities, but contains windblown dust primarily from the FMC and J.R. Simplot Company ore handling areas. In addition, some slag was applied to the surface for roads and parking. This property is within the area identified for potential re-development under the Power County Development Authority (PCDA) Development Agreement. The excavation and consolidation at RA-J under this alternative would involve excavation (surface scraping) to a maximum of 6 inches below ground surface (bgs) or mechanically mixing the soil by tilling in place to reduce surface COC concentrations below a level of concern.
At RA-B, C, D and E: Underground process piping that remains in place may contain elemental phosphorus (P4), precipitator solids, and/or phossy solids. Containment of the underground process piping under an ET cap will prevent direct exposure to phosphorus under conditions that may cause it to spontaneously combust.
At RA-A: Potential P4 residues in underground storm sewer piping would be cleaned as part of the remedial action under this alternative. These 16-inch, reinforced concrete sewer pipes would be cleaned to remove potential residual P4 and soil/materials potentially containing metal and radiological constituents. These cleanout sludges would be disposed of off-site either in an appropriate landfill or incinerated, depending on the material found in the sludge. This approach would allow these storm sewers to remain in place for continued stormwater management.
EPA acknowledges that flexibility will be built into the selected soil remedy to allow the following refinements during remedial design:
- Integration of a re-use/redevelopment option if identified during remedial design.
- Consolidation of contaminated soil to minimize the size of caps (i.e. flexibility to make cap footprint as small as possible).
- Flexibility to optimize the design of the storm water control system and placement of storm water retention basins.
- A contingency for gas extraction and treatment at a later date if there is significant gas build up in the CERCLA remediation areas that would pose a threat to on site workers.
The evaluated groundwater alternatives and their comparative rankings of high, moderate, or low under each criterion are summarized here:
|Evaluation Criterion||Groundwater Alternative 0:
|Groundwater Alternative 1:
Institutional Controls, and Monitored Natural Attenuation
|Groundwater Alternative 2A:
Institutional Controls, LTM, Extract Groundwater at Property Boundary Using Wells for Hydraulic Control and Direct Discharge to POTW
|Groundwater Alternative 2B:
Institutional Controls, LTM, Extract Groundwater at Property Boundary Using Wells for Hydraulic Control, On-Site Treatment, and Discharge to Evaporation/ Infiltration Basin
|Overall Protection of Human Health and the Environment||Low||Moderate||Moderate||Moderate|
|Compliance with ARARs||Low||Moderate||Moderate||Moderate|
|Long-Term Effectiveness and Permanence||Low||Moderate||Moderate to High||Moderate to High|
|Reduction of Toxicity, Mobility, or Volume through Treatment||Low||Low to Moderate||Moderate||Moderate|
|Implementability||High||High||Low to Moderate||Moderate to High|
Annual O&M Cost
In the Proposed Plan, EPA recommended that an Interim ROD Amendment (IRODA) be prepared for the groundwater component of the remedy because it does not appear that any of the groundwater alternatives can achieve the groundwater restoration objective within a reasonable timeframe. However, EPA’s preferred and ultimately IRODA selected groundwater Alternative 2A/B will allow for the collection of additional site-specific data that could be used to determine if groundwater restoration RAOs can be achieved within a reasonable timeframe. If the data indicates that restoration of a portion of the groundwater plume is technically impractical, a waiver could be recommended during the CERCLA five-year review process.
Alternative 2A/B includes source controls, institutional controls, and long-term monitoring (LTM), along with groundwater extraction from the shallow aquifer to provide hydraulic containment of the contaminated groundwater to prevent further downgradient migration of site COCs.
Extraction wells would be located in the northeastern corner of the former FMC Plant Site to capture impacted shallow groundwater. Groundwater modeling indicates that 5 extraction wells would be sufficient and a total combined extraction rate of approximately 530 gallons per minute (gpm) would fully capture migration of impacted groundwater. The extracted groundwater would either be treated at the City of Pocatello water treatment plant under Alternative 2A or treated and discharged to on-site percolation/evaporation basins under Alternative 2B.
The IRODA that EPA issued on September 27, 2012 incorporated EPA’s preferred alternatives described above. On June 10, 2013, EPA issued a Unilateral Administrative Order (UAO) to FMC to implement the IRODA. Under the UAO, FMC has developed and is implementing, at its expense, the remedial design and remedial actions specified in the UAO to meet the IRODA site cleanup requirements. FMC estimates that the remedial work will take 2-3 years to complete and will cost approximately $60 million.