PUBLIC NOTICE | Proposed Leaking UST Case Closure for Case File 0541.01-.04

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

LUST Case File No.: 0541.01-.04

Facility ID No.: 0-002803
Graham County

Facility address: 
Giant #908
300 E. U.S. Highway 70
Safford, AZ 86025

Information

This site is located at 300 E. Highway 70 in Safford. The site is currently operating as a Shell Service Station, located at the northeast corner of U.S. Highway 70 and Kay Lane. The current UST system consists of two 12,000-gallon gasoline USTs, one 8,000-gallon diesel fuel UST and four dispensers.  The original UST system had an additional 12,000-gallon UST (UST #3) which was closed in place in 2004.  Kaibab Industries (Kaibab) was the UST owner/operator prior to Giant Industries (Giant) being the UST owner/operator.  LUST release 0541.01 and .02 were assigned by ADEQ in 1988 and 1996, respectively to gasoline product lines. Kaibab is responsible for these releases under the name Whiting Station No. 130.   LUST releases 0541.03 and .04 were assigned by ADEQ in 2002 and 2005, respectively to the north 12K-galon unleaded UST and the north gasoline fuel dispenser island. The releases were discovered while Giant operated the USTs.

Giant retained several consulting firms to conduct corrective action activities. ADEQ determined that LUST release 0541.03 was within the soil and groundwater contamination area of the preexisting LUST release 0541.01. ADEQ concluded that additional characterization of LUST release 0541.03 was unnecessary, and any corrective actions for LUST release 0541.01 would also remediate the contamination associated with LUST 0540.03.  Western Refining Southwest Inc. (WRS) acquired Giant Industries from Kaibab Industries in May 2007.  WRS and its consultant Tetra Tech conducted corrective actions which included soil boring and monitor well installation and operation and soil vapor extraction (SVE) between 2007 and 2011. In October 2011, Groundwater & Environmental Services, Inc. (GES) to continue corrective actions.  

In 2007, three soil borings were installed to characterize LUST release 0540.04. Trimethylbenzene (TMBs) contamination at a depth of 20 feet bgs was present at SB-1 at concentrations that exceeded applicable regulatory standards. Giant submitted a Site Characterization Report in October 2007 summarizing the data.  ADEQ denied the report in January 2008, and requested another vertical soil boring at the north dispenser island.  SB-4 was installed in May 2008, and completed as monitoring well (MW-6).  Soil samples collected at 15 and 20 feet bgs contained benzene, toluene, ethylbenzene and xylene (BTEX), TMBs, and naphthalene at concentrations that exceeded applicable regulatory standards. These compounds are all volatile organic compounds (VOCs).

SVE operation began in June 2008 and was permanently shut down in November 2011 due to low contaminant mass removal rates. Low contaminant removal rates limit the cost-effectiveness of the system. The post remediation groundwater data collected in February 2018 shows that the VOC concentrations have significantly decreased so that only MW-6 shows any VOC (benzene) in concentrations that exceed an applicable regulatory standard.   Other VOCs were reported but at concentrations below their applicable regulatory standard.

A site specific risk assessment and detailed file/information search have been completed. Based upon the results of  remedial activities and site specific information provided by GES, 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 (A) and (B) allows case closure of a LUST site with groundwater contamination above the Aquifer Water Quality Standard (AWQS) or Tier 1 Corrective Action Standards.

Review Document 

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

Public Comment Period 

Dates: May 29, 2018  June 29, 2018

Comments may be submitted as follows:
     By Email | Send Email > 
     By Mail (Must be postmarked or received by June 29, 2018):

       ADEQ
       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 >