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NPL Site Narrative for Stoker Company

Imperial, California

Federal Register Notice:  July 29, 1991

Stoker Co. operates at 3390 Dogwood Road in a sparsely populated agricultural area in Imperial, Imperial County, California. The company has been an aerial pesticide applicator and pest control supplier since 1966 and in 1990 employed 45 people. A canal that runs along the southern and eastern borders of the airstrip delivers water to a residence less than 80 feet from the site, wetlands, and a commercial fishery. The wetland is located along the entire length of the airstrip and provides habitat for four endangered or threatened species. The fishery produces catfish for human consumption and is located 0.25 mile from the site.

Wash waters from the cleaning of pesticide application equipment are sprayed onto a 20-acre land treatment area on-site consisting of a dirt road and landing strip. Occasionally rinse waters from the rinsing of hoppers in the aircraft and pesticide containers were also sprayed on this area. The disposal of wash waters is permitted under Waste Discharge Requirements issued by the California Regional Water Quality Control Board (CRWQCB) in October 1974 and June 1988. Under this permit, Stoker is required to sample the unsaturated zone and ground water beneath the site. The requirements indicate that approximately 300 gallons of pesticide rinsewater per day were disposed of in the land treatment area in the 1970s, dropping to approximately 100 gallons per day sometime prior to 1988. In 1989, Stoker submitted a closure plan for the land treatment unit to CRWQCB and indicated that it would cease spraying wash waters on-site. Stoker later reconsidered and continues to spray wash waters on-site.

The site first came to the attention of local authorities in May 1988 when birds and fish were killed in a pond in a nearby residence. The California Department of Fish and Game and the Department of Food and Agriculture determined that the fish tissue was contaminated by several pesticides. The pond was subsequently closed.

Shortly after the fish were killed, a warehouse containing pesticide supplies burned to the ground. The company subsequently removed 300 tons of contaminated soil to a landfill regulated under Subtitle C of the Resource Conservation and Recovery Act. Also on the site is an area where empty pesticide bags and boxes were burned.

In December 1988, EPA sampled on-site soil, the nearby canal, and the pond. Analyses identified several pesticides, including dacthal, diazinon, chlorpyriphos, and mevinphos, in the canal. Sediment and air samples EPA collected in 1989 indicated pesticides had been released to the air and nearby wetland. Approximately 130 people live within 1 mile of the site. The plant's 45 employees are exposed to contaminated soil. A family that formerly lived on a portion of the property moved due to the contamination.

Although the site is located in an agricultural area where pesticides are widely used, the levels in air, surface water, sediment, and soil samples significantly exceed background concentrations. Due to the poor quality of ground water and surface water in the area, most people rely on bottled water for their drinking water.

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 ATSDR - ToxFAQs (http://www.atsdr.cdc.gov/toxfaqs/index.asp) or by telephone at 1-888-42-ATSDR or 1-888-422-8737.

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