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Naval Industrial Reserve Ordinance Plant (NIROP)

Site Information

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Contact Information

Community Involvement Coordinators
Patricia Krause (krause.patricia@epa.gov)
312-886-9506 or 800-621-8431, ext. 69506

Remedial Project Manager
Sheila Desai (desai.sheila@epa.gov)
312-353-4150 or 800-621-8431, ext. 34150


(where to view written records)



The Naval Industrial Reserve Ordnance Plant (NIROP) site is an 83-acre site located about 700 feet east of the Mississippi River in Fridley, Minnesota. The U.S. Navy and its contractors have produced advanced weapons systems at the facility since 1940. In 1981, trichloroethylene (TCE) was discovered in on-site groundwater wells and in the city of Minneapolis's drinking water treatment plant intake pipe, which is now located in the Mississippi River about 4,900 feet downstream from the site. There were no existing federal drinking water standards for TCE in 1981, but the wells on the NIROP site were shut down in April 1981 as a precautionary measure.

The Navy, USEPA, and MPCA began environmental investigations at NIROP in 1983 and work continues today. The environmental cleanup program at NIROP identified volatile organic compound (VOC) contamination in both soil and groundwater. Soil investigations were conducted by the Navy on the land outside the NIROP building in 1983, 1992, and 1996, resulting in the removal and off-site disposal of 2,200 cubic yards of soil and 97 drums and 12 small containers of waste that were found buried on the site.

Studies conducted at NIROP in 1984 and 1988 indicated that groundwater originating from the site and contaminated primarily with TCE was flowing into the Mississippi River at TCE concentrations above the Safe Drinking Water Act maximum contaminant limit (MCL) for TCE (5 ppb). The Navy presented the groundwater cleanup plan for NIROP to the community in a public meeting held in Fridley in 1990. The plan included pumping the contaminated groundwater to the surface with extraction wells, treating the water to remove TCE and other VOCs, then discharging the clean water into the Mississippi River. The overall goal of the groundwater cleanup design is to contain the groundwater contamination within the NIROP site boundary to prevent additional movement of contaminated groundwater off-site.

Groundwater treatment has been ongoing at NIROP since September 1991 and continues today. Additional wells were installed, replaced, and/or taken out of service over the years, along with treatment system upgrades designed to maximize system performance and to gather additional information. More than 4.3 billion gallons of groundwater have been treated since 1991, resulting in a recovery of over 38,000 pounds of TCE, accounting fora considerable reduction in the VOC concentrations at the NIROP site. The system is doing what it was designed to do, but it will take time for the groundwater to reach cleanup goals at the current pace. The Navy is continuously monitoring the system and evaluating new cleanup options to identify actions that may help speed up the process and allow the site to reach cleanup goals faster. In 2003, the Navy remediated a portion of Anoka County Park using application of vegetable oil to reduce TCE concentrations in groundwater from over 17,000 parts per billion to less than 500 parts per billion today.

Potential health risks exist for individuals who ingest or come into direct contact with contaminated groundwater or soil. Because the NIROP site is fenced and no private wells are located in the nearby area, no residents are currently being exposed to the contaminants. Volatile organic compounds have not been detected in water from the city of Minneapolis municipal water intake pipe in the Mississippi River since the 1980s.


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