The Prewitt Abandoned Refinery near Prewitt, McKinley County, New Mexico was placed on the National Priroties List (NPL) by the U.S. Environmental Protection Agency on 30 August 1990. The NPL is the list of national priorities among the known releases or threatened releases of hazardous substances, pollutants, or contaminants throughout the United States and its territories.

The NPL is part of the Superfund program, the common name for the United States environmental policy officially known as the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), enacted by the United States Congress on December 11, 1980 in response to the Love Canal and Times Beach disasters. The Superfund law was created to protect people, families, communities and others from heavily contaminated toxic waste sites that have been abandoned. Many of the contaminants at Superfund sites are also regulated under the Resource Conservation and Recovery Act (RCRA).

Background

The Prewitt Abandoned Refinery is located about one-half mile west of the Prewitt Post Office, McKinley County, New Mexico. The site consists of two separate parcels, one consisting of 68.2 acres and the other consisting of 6.8 acres. The refinery was in operation between 1938 and 1957. In July 1957, the refinery was shut down and the refinery and accompanying structures were subsequently dismantled. Remnants and debris remained after the refinery was dismantled, including piping, waste pits, a separator structure, and other structural material. The Site was covered with scattered demolished structures and foundations, sparse desert vegetation, and exposed fill. The Navajo Indian Tribe has owned the property since December 1966.

Although the site is located in rural area, several off-site residences are located within 1,500 feet of the site. In December 1982, the New Mexico Environmental Improvement Division detected benzene in a nearby private well, and in May 1986 detected benzene and xylenes in an onsite well to a depth of 17 feet. Wells within 3 miles of the facility provide water to a public community water system, a public noncommunity water system, private homes, and livestock. An estimated 1,600 people are served by ground water.

Contamination

The surface soil and shallow ground water underlying the site have been contaminated with RCRA listed wastes including slop tank contents, primary separator sludge, and secondary separator floats mixed with petroleum hydrocarbon products from past refinery-related activities. Benzene, toluene, xylene, polynuclear aromatic hydrocarbons, chromium, and lead were detected in on-site soil samples and on-site and off-site groundwater samples. Site-related contaminants have also been detected in off-site private wells. The most likely pathways for contaminants to migrate from on-site to off-site areas include those associated with groundwater and soil. Human exposure to site contaminants is most likely to occur via ingestion and inhalation of, or dermal contact with, contaminated groundwater and soil. The site is of potential public health concern because of elevated levels of contaminants in groundwater and soil.

Summary of remedial actions

The U.S. Environmental Protection Agency (EPA) has conducted a second five-year review of the remedial actions implemented at the Prewitt Superfund Site (Site) in Prewitt, New Mexico. This second five-year review of the Site covers the period from May 2000 to April 2005. The surface remedial actions met all remedial action objectives, and the EPA deleted the surface portion of the Site from the NPL in January 1998. However, the subsurface remedy at the Site is not functioning as expected but is protective of human health and the environment in the short term. For the remedy to function in the long term continued monitoring and some form of institutional controls are necessary.

The subsurface remedy included Non-aqueous Phase Liquid (NAPL) extraction; nutrient injection; ground water extraction; and treatment and reinjection. The Phase I Subsurface Remediation completion has accomplished the following:

• Recovered over 5,600 gallons of NAPL by liquid recovery.
• Removed over 520,000 lbs. (approximately 80,000 gallons) of volatile hydrocarbon (NAPL),
• including about 21,000 lbs. of BTEX by SVE.
• Removed the volatile fraction of NAPL by SVE such that the site-specific contaminant target levels for BTEX have been attained.
• Reduced toxicity, volume, and mobility of NAPL.
• Reduced ground water BTEX concentrations in source areas.
• Effectively contained contaminated ground water.

Sources

• United States Environmental Protection Agency, Second Five-Year Review Report For Prewitt Superfund Site Prewitt, New Mexico, September 2005.
• United States Environmental Protection Agency, NPL Fact Sheet:Prewitt Abanadoned Refinery, Prewitt, New Mexico, August 2008.