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NPL Site Narrative for Apache Powder Co.
APACHE POWDER CO.
St. David, Arizona
Federal Register Notice: August 30, 1990Conditions at proposal (June 10, 1986): Apache Powder Co. manufactured nitroglycerine-based explosives from 1922 to 1963 and ammonium nitrate from 1963 to the present at a 945-acre property near St. David, Cochise County, Arizona. Prior to 1971, all waste water was drained to on-site dry washes that are tributaries to the San Pedro River. Since that time, waste water has been contained in unlined ponds ranging from 6 to 8 feet deep. About 15 ponds covering 10 acres are present on-site, of which 5 to 10 were in use at any one time. The waste water contains elevated levels of nitrate. In 1982, the Arizona Department of Health Services (ADHS) found more than 60,000 parts per million of nitrate-nitrogen in waste water. Soil in the bottom of the dry ponds also contained high levels of nitrate-nitrogen, as did ash in a burning ground located in a dry wash.
In 1980, EPA detected toxic heavy metals in one lagoon at levels above drinking water standards. In 10 shallow wells believed to be downgradient of Apache Powder, ADHS and the Southeastern Arizona Governments Organization detected nitrate-nitrogen in excess of drinking water standards. At one time, 8 of the 10 wells were used for drinking water.
A deeper artesian aquifer is not contaminated to date, but there may be danger of contamination in the future.
ADHS has also detected elevated nitrate levels in the San Pedro River, which borders the plant.
Status (June 24, 1988): After this site was proposed in June 1986, procedural and technical issues arose. Hence, EPA re-evaluated the site and changed its score on the Hazard Ranking System, which EPA uses to assess sites for the NPL. Consequently, EPA is reproposing this site to allow an additional 60-day comment period.
Status (August 30, 1990): In the summer of 1988, EPA confirmed the presence of nitrates in private wells and in the San Pedro River and also found elevated levels of nitrates and heavy metals in pond sediments.
EPA has issued a Unilateral Administrative Order requiring Apache Nitrogen Products (formerly Apache Powder Co.) to conduct a remedial investigation/feasibility study (RI/FS) to determine the type and extent of contamination at the site and identify alternatives for remedial action. Field work is underway. The RI/FS is scheduled to be completed in the spring of 1992.
For more information about the hazardous substances identified in this narrative summary, including general information regarding the effects of exposure to these substances on human health, please see the Agency for Toxic Substances and Disease Registry (ATSDR) ToxFAQs. ATSDR ToxFAQs can be found on the Internet at http://www.atsdr.cdc.gov/toxfaq.html or by telephone at 1-888-42-ATSDR or 1-888-422-8737.