PUBLIC NOTICE | Proposed Leaking UST Case Closure for Case File 2672.01-.02

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

LUST Case File No.: 2672.01-.02

Facility ID No.: 0-007862
Pinal County

Facility address: 
Frog Service Center (former ARCO No. 1488)
381 South Arizona Boulevard
Coolidge, AZ 85228


This site was a former ARCO branded service station between 1958 and 1974.  An automotive repair shop (Ed’s Body Shop) and a used vehicle sales lot (Dreamline Motors) have also operated at the site after the ARCO station closed. Gasoline sales reportedly ceased in 1975, and the three underground storage tanks (USTs) reportedly were closed-in-place between 1975 and 1983 and were located south of the building structure.  An additional 300-gallon waste oil tank was removed in 1995 and the UST was located where the existing building sits.

In 1993 a voluntary site assessment was performed as part of a property transfer.  Soil contamination was identified and LUST case #2672.01 was assigned to the gasoline USTs.  Between 1995 and 1999, multiple soil borings and three monitoring wells (MW-2 through MW-4) were installed. A nested shallow vapor, monitoring well and sparge well was also installed (MW-1). In October 1999, ADEQ issued a letter stating that the site was designated as having multiple LUST releases and LUST case #2672.02 was assigned to the former dispenser pump island. ADEQ issued a letter in May 2000 that the soil contamination was fully characterized, but the groundwater plume needed additional characterization due to an adjacent LUST site (Ray Bell Oil #416) located to the northwest and down gradient of this LUST site.   In September 2003, ADEQ issued a letter rescinding the requirement for additional characterization of the groundwater based on the denial of property access from the Arizona Department of Transportation (ADOT), and a review of the LUST files for both sites. In 2004, four additional groundwater monitoring wells were installed.  In March 2011, the current consultant for Tesoro Companies, Inc [Antea Group], submitted a Corrective Action Plan to ADEQ proposing a series of soil vapor extraction (SVE) and air sparge (AS) events.  However, the consultant was denied site access by the property owner for any reason. In 2013, the property owner only allowed site access during evening hours and site work was limited to groundwater gauging and sampling. The property owner would not allow any intrusive work or the placement of any remediation equipment at the site.  In 2015, Antea Group again attempted to get off site access from ADOT to install a monitoring well in the center median of State Route 87 (Arizona Boulevard).  The request was again denied. Antea Group conducted a soil vapor survey in 2017 to assess the potential vapor intrusion risk from any remaining subsurface soil contamination. 

Current data provided by Antea Group, and all other available site information has been used by ADEQ to determine whether remaining levels of contaminants at the site are adequately protective of human health and the environment.  A site specific risk assessment and detailed file/information search were also completed.  Volatile organic compound (VOC) analytical groundwater results in MW-7 show that 1, 2-dichloroethane (1, 2-DCA) concentrations remain above Aquifer Water Quality Standard of 5.0 µg/L. 1, 2-DCA and ethylene dibromide (1, 2-DCA and EDB) were leaded gasoline additives.   Benzene concentrations in MW-5 exceed the AWQS of 5.0 µg/L. The results for all other monitoring wells show no contamination present and is available in the LUST file.

Based upon the results of remedial activities and site specific information, the above-referenced LUST site is eligible for alternative LUST closure under Arizona Revised Statutes (A.R.S.) §49-1005(E).  Arizona Administrative Code (A.A.C.) R18-12-263.04 allows case closure of a LUST site with groundwater contamination above the Arizona Aquifer Water Quality Standards (AWQS) or Tier 1 Corrective Action Standards.

Review Document 

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

Public Comment Period 

Dates: July 17, 2018  August 17, 2018

Comments may be submitted as follows:
     By Email | Send Email > 
     By Mail (Must be postmarked or received by August 17, 2018):

       Debi Goodwin
       Waste Programs Division
       1110 W. Washington Street
       Phoenix, AZ  85007 

Documents may also be reviewed in person at the ADEQ Record Center | Learn More >