Waste Programs Division: Underground Storage Tanks
Tank pull

The Waste Programs Division ensures proper operation and maintenance of regulated underground storage tank systems by conducting periodic inspections and assisting owners and operators in complying with applicable state and federal regulations. Enforcement actions are taken in cases of significant non-compliance. The division also protects public health and the environment through oversight, investigation and cleanup of soil and groundwater contamination caused by releases from underground storage tanks.

The Underground Storage Tank (UST) Program regulates the majority of USTs in Arizona, with the exception of those on Indian Lands. Nearly all underground storage tanks at these sites contain petroleum. These sites include marketers who sell gasoline to the public (such as service stations and convenience stores) and non-marketers who use tanks solely for their own needs (such as fleet service operators and local governments).

What is a "UST"?

An underground storage (UST) tank system is a tank and any underground piping connected to the tank that has at least 10 percent of its combined volume underground. The federal UST regulations apply only to underground tanks and piping storing either petroleum or certain hazardous substances.

What is "Petroleum"?

Generally, refined petroleum is divided into three categories: gasoline, high-end liquid hydrocarbon fuels such as diesel, No. 2 fuel oil, kerosene, aviation gasoline, and jet fuels, and hydrocarbon oils, such as lubricating oils and other fuel oils.

What is MTBE?

Methyl tertiary butyl ether (MTBE) is a synthetic, flammable liquid fuel additive made principally from natural gas and other chemical compounds. It is blended with gasoline for the purpose of increasing the octane level and reducing vehicular emissions (CO2) and ozone-forming air pollutants. MTBE is a potential human carcinogen that has been detected nationwide in groundwater and some drinking water sources as a result of leaking USTs, accidental spills and overfills at gasoline pumps.

In September 2003, the U.S. EPA announced its proposed approval of Arizona's revised air quality plan for the Phoenix metropolitan area that eliminates the need for MTBE in summertime Cleaner Burning Gasoline, which is used to reduce ozone-forming emissions in the Valley.

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What is a "Regulated UST?"

Generally, any UST containing petroleum or hazardous substances larger than 110 gallons and operated on or after Jan. 1, 1974, with the exception of USTs used for on-site heating such as home heating oil USTs, is a regulated UST. Over a 10-year period, between Dec. 22, 1988 and Dec. 22, 1998, all operating tanks installed before the 1988 date were required to close or upgrade. The upgrade requirements included three components to prevent a release:

  • Corrosion protection (for steel USTs and piping)
  • Spill prevention
  • Overfill prevention

Compliance with these and other operational and administrative requirements is the responsibility of the UST Program.

Links Within the UST Program

Contact Us LUST Stakeholder Meeting Information
Delivery Prohibition Outreach
Financial Responsibility Public Notices
Forms and Guidance Route 66 Initiative
Inspections & Compliance State Assurance Fund
Leaking UST Investigations & Cleanups UST Policy Commission and Technical Appeals Panel
Leaking Underground Storage Tank Enforcement Unit Video Gallery

Delivery Prohibition

On January 1, 2009 Arizona Revised Statute (ARS) § 49-1023 gave ADEQ the authority to issue a stop use order to the owner and operator of an Underground Storage Tank (UST) system if the UST is in violation of Arizona's UST rules and regulations and the continued operation of the UST may result in a continued release or a new release from the UST. The stop use order becomes effective immediately on issuance and suspends the use of the underground storage tank until the owner and operator has returned the UST to full compliance with Arizona's UST rules and regulations.

More information on delivery prohibition and stop use orders may be found in Arizona Revised Statute (ARS) § 49-1023 Leaving ADEQ Web site.

Facilities currently under a stop use order have delivery prohibition in effect. Facilities will be removed from this list within five business days after the department determines that the requirements in Arizona Revised Statute (ARS) § 49-1023 have been met.

Facility Name: Mercado de Amigo
Facility Location: 1529 N. Avenue 64E, Dateland, AZ
Stop-Use Order Issue Date: July 15, 2014
Underground Storage Tank Affected: All tanks at this site are subject to delivery prohibition. They are as follows:
  • UST number 1: A 8,000 gallon, single compartment, gasoline UST
  • UST number 2: A 8,000 gallon, single compartment, diesel UST
Facility Name: Killmer's Kountry Store
Facility Location: 115 Highway 188, Globe, AZ
Stop-Use Order Issue Date: July 11, 2014
Underground Storage Tank Affected: All tanks at this site are subject to delivery prohibition. They are as follows:
  • UST number 1: A 10,000 gallon, single compartment, gasoline UST
  • UST number 2: A 10,000 gallon, single compartment, diesel UST
Facility Name: One Stop 2
Facility Location: 379 South Main Street, Snowflake, Navajo County, Arizona
Stop-Use Order Issue Date: March 16, 2012
Underground Storage Tank Affected: All tanks at this site are subject to delivery prohibition. They are as follows:
  • UST number 6: A 10,000-gallon, single compartment, gasoline UST
  • UST number 9: A 2,000-gallon, single compartment, gasoline

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Financial Responsibility

ADEQ is seeking to ensure that UST owners and operators in Arizona are in compliance with federal and state financial responsibility requirements.

UST owners and operators are required to maintain the financial means to cover investigation and cleanup costs and third-party property and bodily injury liability claims associated with releases from leaking USTs.

Read a detailed summary of the UST Financial Responsibility Requirements.

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Video Gallery

Fountain Hills Soil Vapor Sampling

Located approximately thirty miles northeast of downtown Phoenix, Fountain Hills, Arizona is known for the towering man-made fountain located in the center of town. ADEQ was there, working in a residential neighborhood near an elementary school as part of its State Lead underground storage tank program. The Lead program is so named because ADEQ assumes the responsibility for corrective actions where the responsible party is unknown, unwilling, or unable to undertake site investigations and cleanups. The purpose of testing soil vapor is to determine whether there is any risk to public health from the contaminated groundwater beneath the area. Twenty years ago there was a gas station across the street from the school that leaked contaminants into the soil and water. If there is contamination that requires cleanup, ADEQ will work to mitigate the risk so the public will be safe. The work is paid for by the penny-per-gallon tax on all fuels sold within Arizona.

Red Rock UST Removal

Located between Phoenix and Tucson off Interstate 10, Red Rock, Arizona is a mostly an agricultural area, although the city has recently seen construction of tract home communities. ADEQ was at an abandoned gas station as part of their State Lead program, so named because ADEQ takes charge of the underground storage tank removal and assessment for possible soil and groundwater contamination because the property has been abandoned. At this site, ADEQ removed three 8,000 gallon steel tanks used for gasoline storage and one 550 gallon tank used to house hazardous materials in order to adequately assess contamination risks. If there is contamination that requires cleanup, ADEQ will work to mitigate the risk so the area can be redeveloped.