PUBLIC NOTICE | Proposed Leaking UST Case Closure for Case File 5204.01

ADEQ is considering closure of the following leaking underground storage tank (LUST) case:

LUST Case File No.: 5204.01     

Facility ID No.: 0-008147
Pinal County

Facility address: 
Former Ernie's Station
265 W. Coolidge Avenue
Coolidge, AZ 85128


The former Ernie’s Station is located at the southeast corner of South 3rd Street and West Coolidge Avenue (265 W. Coolidge Avenue) in Coolidge. This former service station is currently being used as a car wash facility. A release was reported to ADEQ during removal of gasoline underground storage tanks (USTs) in 2000 located east side of the building.  A 550 gallon used oil UST located south side of the building was also removed during this time. The contamination eventually reached groundwater. Initial site investigation included soil borings and the installation of five monitoring wells. Contamination in soil and groundwater was primarily limited to the nearby source area with high levels of benzene, 1,2-dichloroethane (1, 2-DCA) and ethylene dibromide (EDB). 1,2-DCA and EDB are lead scavengers which indicate a leaded gasoline release.

The property owner requested the State Lead Unit’s assistance in December 2001 to perform corrective action. Remediation included operation of an ozone sparging and soil vapor extraction (SVE) system beginning in March 2011. Due to decrease in groundwater level, five additional deeper sparge wells were installed in January 2013. Soil samples collected during the installation showed residual presence of 1,2,4-trimethylbenzene  and 1,3,5-trimethylbenzene (TMBs) and naphthalene at 30 and 75 feet below ground surface (bgs). A higher flow air compressor was brought to operation replacing the ozone sparging system in December 2013. The remediation system was shut down in May 2015 based on low contaminant recovery.  Approximately 46,182 pounds of total volatile fuel hydrocarbons were removed from the subsurface.

Based on the soil properties analyses, soil in the former tank pit at a depth of 5 feet bgs is sandy loam and native soil at a depth of 75 feet bgs (representative of native soil above groundwater) is loam to clay loam. The groundwater flow direction is approximately northwest. The depth to groundwater is approximately 80 feet bgs.

Groundwater data has been collected since July 2002. Several volatile organic compounds (VOCs) historically have been present at concentrations that exceed the applicable regulatory standards. To complement the ozone sparging and SVE, three rounds of PersulfOx™ injections were done to remediate the groundwater. These injections were done between 2014 and the end of 2015. Post injection groundwater sampling indicated VOC concentrations were reduced to below applicable regulatory standards (in most cases to non-detect) in all wells but monitoring well (MW) MW-3 as of March 2015.

Review Document 

Review results of remedial activities and entire public notice | View/Print >

Public Comment Period 

Dates: April 3, 2017  May 3, 2017

Comments may be submitted as follows:
     By Email | Send Email > 
     By Mail (Must be postmarked or received by May 3, 2017):

       Samar Bhuyan
       Waste Programs Division
       1110 W. Washington Street
       Phoenix, AZ  85007 

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