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Record of Decision System (RODS)



City & State:  IDAHO FALLS  ID  83401
EPA ID:  ID4890008952
EPA Region:  10
NPL Status:  Currently on the Final NPL
ROD Type:  Record of Decision
ROD ID:  EPA/ROD/R10-92/040
ROD Date:  06/02/1992
Operable Unit(s):  23
Media:  Soil, Debris
Contaminant:  Organics, Inorganics, Natural Decomposition Products
Abstract:  SITE HISTORY/DESCRIPTION: The U.S. DOE Idaho National Engineering Laboratory (INEL), established in 1949, is located 32 miles west of Idaho Falls, Idaho. The facility occupies 890 square miles, and land use in the area is predominantly industrial. The Snake River Plain Aquifer, which underlies the INEL, has been designated as a sole source, Class I, aquiferpursuant to the Safe Drinking Water Act. Within the INEL is a 270-square- mile area, formerly known as the Naval Proving Ground (NPG), which was used prior to World War II for naval artillery testing, explosives, storage bunker testing, and ordnance disposal. Investigations by site personnel have resulted in the discovery of numerous unexploded ordnance devices, such as 3 -to 16-inch artillery shells, partially exploded 125- to 2,000-pound bombs, anti-tank mines, and depth charges. This ROD addresses OU23, which covers six locations on the site: the CFA gravel pit, the storage bunkers north of Idaho Chemical Processing Plant, the National Oceanic and Atmospheric Grid, CFA Building 633 Zone, Fire Station II Zone, and Power Line Road. Unexploded ordnance has been found on the ground surface in most of these areas. It is estimated that 150 unexploded ordnance will be found and detonated during this remedial action. Areas of soil are also contaminated with explosive compounds at the ground surface, or will become contaminated by detonation activities. This interim ROD addresses ordnance in the six NPG areas and associated soil contamination. Future RODs will address remaining ordnance areas for which insufficient information exists at this time, final remedies for soil contamination, and all of the Waste Area Group 10 (WAG 10) at the INEL site. The primary contaminants of concern affecting the soil and ordnance debris are organics; inorganics; and natural decomposition products. PERFORMANCE STANDARDS OR GOALS: Action levels for soil were determined based on health-based criteria and include TNT 44 mg/kg and RDX 18 mg/kg. A screening level for DNT has not been developed as it is a breakdown product of TNT. Soil at or above these screening levels will be excavated, containerized, and transported to an offsite incinerator. Any resultant ash will be disposed of by the incinerator facility. Containerized soil will be sampled and analyzed for TCLP analytes to determine whether they should be classified as a RCRA waste. INSTITUTIONAL CONTROLS: Not provided.
Remedy:  SELECTED REMEDIAL ACTION: The selected interim remedial action for this site includes conducting soil sampling of the detonation areas; excavating, containerizing, and transporting an estimated 185 cubic yards of soil exceeding action levels offsite for treatment using incineration, with offsite disposal of residuals; researching historical records pertaining to ordnance activities at INEL; conducting a field search of the six NPG areas for unexploded ordnance; controlled onsite thermal treatment (detonation) of any identified ordnance, with onsite disposal or recycling of any residual metal debris; and posting signs where the public has access to ordnance areas. The estimated present worth cost for this remedial action is $2,359,500. No O&M costs are associated with this remedial action.
Text:  View full-text ROD [ 49K ]
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