Stone Avenue and Grant Road | Site History

2021 – 2022: The Final Remedy is implemented at the Site. Ongoing Operations, Maintenance and Monitoring (OMM) is conducted.

2020: The Feasibility Study (FS) Report and Proposed Remedial Action Plan (PRAP) were finalized in February. The Record of Decision was signed in June.

2018 – 2019: Additional soil-gas and groundwater investigations were conducted as part of the Remedial Investigation (RI). The Final RI and Feasibility Study (FS) Work Plan were finalized in October.

2017: The site was listed on the WQARF Registry in January. The RI began by investigating groundwater and soil-gas within the Site investigation area. An Early Response Action (ERA), a Soil Vapor Extraction (SVE) system, was implemented in November.

2016: ADEQ completed the Stone Avenue and Grant Road Preliminary Investigation (PI) in February.

2015: Tetrachloroethene (PCE) and trichloroethene (TCE) were found at a Leaking Underground Storage Tank (UST) facility at the northeast corner of the Stone and Grant WQARF site at concentrations of 515 micrograms per liter (µg/L) and 5.73 µg/L, respectively.

2014: The City of Tucson conducted soil and soil-gas sampling at the site. PCE was not detected above laboratory detection levels in the eleven soil samples collected from four soil borings. PCE was detected in all four sub-slab soil-gas samples ranging from 22,000 to 450,000 micrograms per meter cubed (µg/m3).

2005: PCE was detected in the regional aquifer in one of two Sleepy Hollow Mobile Home Park domestic wells, located approximately 0.6 miles from the Stone and Grant WQARF site at a concentration of 2.8 µg/L.

1940s – 2000: Dry cleaning facilities operated at the site. In 1963, a gas explosion occurred at a dry cleaners located onsite. Natural gas and dry cleaning solvent containing PCE were released. The explosion destroyed the existing building. The facility was rebuilt, and dry cleaning operations resumed.