Location: South Eastern Corner of the Intersection of Hanna and Guano Roads, Pinal County, Arizona

Discovery Date: 1983

Contaminants of Concern (COCs): Pesticides, including toxaphene, dichlorodiphenyltrichloroethane (4,4, -DDT), dichlorodiphenyldichloroethane (4, 4, - DDE) chlordane, and dieldrin

Affected Media: Soil

What Are My Health Risks?

For Soil | There is little to no health risk unless there is contact with skin or ingestion of contaminated soil.

Site Summary:  

The former PureGro Company operated a bulk fertilizer and pesticide distribution facility at the site located at the intersection of Hanna and Guano Roads, Pinal County, from 1955 to 1984. The facility typically received, stored, and distributed fertilizers and pesticides, and performed vehicle and equipment rinsing and maintenance as part of its routine operations. PureGro’s operations included maintenance of an evaporation pond, underground and aboveground storage tanks, warehouses, office buildings, loading docks, and storage sheds.

Union Oil Company of California (Unocal) acquired PureGro in 1961. Chevron Corporation (Chevron) acquired Unocal in 2005.

Pesticides including toxaphene, dichlorodiphenyltrichloroethane (4,4, - DDT), dichlorodiphenyldichloroethane (4, 4, - DDE) chlordane, and dieldrin were discovered at the PureGro property and off site at several adjacent properties at levels that exceeded the respective Arizona Soil Remediation Levels. Chevron entered into a Consent Order with ADEQ to determine the extent of the contamination and implement corrective actions. As part of the corrective actions, Chevron is required to clean up impacted properties to approved standards based on property usage.

Investigation/Corrective Action:

• Contamination was initially identified by EPA in 1983, prior to ADEQ’s formation in 1986;
• Between 1986 and 2005, various consultants were tasked with investigating the site, which indicated pesticide contamination above regulatory standards.
• After 2005, Chevron collected samples at the adjacent properties on several occasions adding to the identified extent of contamination;
• Chevron entered ADEQ’s Voluntary Remediation Program (VRP) in February 2020 to perform additional investigations and begin implementation of the necessary corrective actions;  
• Between 2020 and 2021, ADEQ’s Hazardous Waste Program assumed oversight of the PureGro site, and Chevron entered into a Consent Order with ADEQ (currently in effect) to develop and implement approved corrective actions to clean up contaminated properties;
• Chevron submitted a Remedial Action Plan (RAP) to clean up the site.  The soil from adjacent properties with contaminants above site-specific remediation standards will be placed on the Chevron parcel. Soil located on the Chevron property with potential hazardous waste characteristics will be removed and properly disposed.  The Chevron parcel will have a restricted covenant called a declaration of environmental use restriction (DEUR) recorded on the property.  
• To better define the areas for excavation at the contaminated properties, Chevron collected additional samples between December 2023 and May 2024.
• In March 2025, Chevron submitted the final comprehensive RAP. Upon ADEQ’s approval of the comprehensive Remedial Action Plan, Chevron will begin implementation of clean-up actions.