Superfund/CERCLA Program

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).

SUPERFUND PHASE 1: 1998 CERCLA Record of Decision (ROD)

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 surroudning area that may have been affected by plant operations.

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 the following cleanup actions for the FMC Plant Subarea, now referred to as the FMC Plant Operable Unit (OU):

  • Cap the Old Phossy Waste Ponds and the Calciner Solids Storage area, and line the Railroad Swale to reduce infiltration of rainwater,
  • Conduct maintenance at capped areas to meet EPA standards,
  • Monitor ground water to prevent use of contaminated ground water for drinking purposes,
  • Implement a ground water extraction/treatment system if contaminated groundwater migrates beyond FMC-owned property and into adjoining springs or the Portneuf River at unacceptable levels,
  • Conduct maintenance on the groundwater extraction and treatment system, if implemented, to meet EPA standards, and
  • Implement land use controls to prevent future residential use.

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. As a result, FMC has not been able to fully implement the 1998 ROD. Nevertheless, FMC has done the following consistent with that ROD:

  • Monitored groundwater at wells on the FMC Plant OU,
  • Performed periodic supplemental groundwater investigation/monitoring programs or events as requested by EPA or IDEQ, and
  • Placed deed restrictions that prohibit any future residential use of the FMC properties at the EMF Site.

Without an entered consent decree to implement the 1998 ROD for the FMC Plant OU, FMC has been unable to implement the remaining cleanup remedies.

SUPERFUND PHASE 2:

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.

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.

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 is expected to soon release a Proposed Plan for the FMC plant site. The SFS evaluations of the soil and groundwater remedial alternatives are summarized below, followed by EPA’s preferred alternative. After EPA receives public comment on the Proposed Plan, EPA will develop an Amended ROD that will formally designate the remedial action to be conducted at the FMC Plant OU. Following negotiations and court approval of a consent decree, FMC will then proceed with implementing the remedial action.

Soil Alternative

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:
"No Action"		 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
Implementability High High High Moderate
Cost Effectiveness
Capital Cost
Annual O&M Cost
NPV Cost		 High
$0
$0
$0		 High
$28.4M
$513K
$32.7M		 Moderate to High
$43.6M
$602K
$47.2M		 Low
$76.8M
$547K
$81.6M

EPA’s Preferred Alternative (Soil Alternative 3) incorporates several common/core remedial actions:

  • institutional controls,
  • grading,
  • stormwater management, and monitoring,
  • Evapotranspiration (ET) and gamma caps.

This figure depicts the extent of the proposed remedial action under EPA’s preferred 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 and 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 is also recommending that flexibility be built into the preferred alternative 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.

Groundwater Alternative

The evaluated groundwater alternatives and their comparative rankings of high, moderate, or low under each criterion are summarized here:

Evaluation Criterion Groundwater Alternative 0:
"No Action"		 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
Short-Term Effectiveness Low Moderate Moderate Moderate
Implementability High High Low to Moderate Moderate to High
Cost Effectiveness
Capital Cost
Annual O&M Cost
NPV Cost		 High
$0
$0
$0		 High
$57K
$71K
$960K		 Moderate
$579K
$712K
$9.6M		 Moderate
$2.7M
$552K
$11.2M

Groundwater Alternative 2b (click to enlarge)

Groundwater Alternative 2b (click to enlarge)

 In the Proposed Plan, EPA is recommending that an Interim ROD Amendment 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 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.

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