AZ Department of Agriculture

Weights and Measures Services Division

Air and Fuel Quality

The Division Fuel Quality program administers the laws and regulations for fuel quality through inspection, analysis and enforcement to help ensure consumers are purchasing quality transportation fuels and to protect air quality. Fuel samples are first tested in the field by investigators and potentially non-compliant fuel is collected for testing at a state of the art laboratory which has the latest analytical equipment and techniques to provide precise results. Additionally, samples are collected for laboratory analysis during randomly scheduled unannounced inspections and when complaints regarding fuel quality are received by the Division.  The Division will follow up with laboratory analysis of gasoline, diesel fuels, high octane racing fuels and biofuels, including biodiesel and E85 fuel ethanol, to make certain they meet state quality and safety standards.


Fuel Quality Non-Conformance:  On several occasions over the past 10 years, the Division has uncovered instances of bad gas or fuel transported from out of state that is not certified or compliant for use in Arizona.  Three recent examples include:

  • In 2012, investigations revealed tarnished fuel samples confiscated at a gas station in Tucson that had received fuel from a company that initially retrieved such fuel from vehicles at junk yards and salvage yards.  In this instance, the fuel had contaminates that could gum up fueling devices and engine parts.  The Division took the fuel off sale. 
  • In 2011, investigations showed that a company that initially retrieved such fuel from vehicles at junk yards and salvage yards was providing fuel that did not meet the CBG requirements in Area A.  The perpetrators were found guilty by Office of Administrative Hearings (“OAH”) and Division penalties of $28,000 were upheld.
  • In 2011, several reports of tarnished fuel leading to damage of car engines were reported in Northern Arizona.  After dispatching a Division investigator to conduct fuel quality testing, the lab results indicated significant contaminates.  This fuel was originally blended at a transmix facility located on tribal lands in Northeastern Arizona, which the Division has no jurisdiction.  As such, the Division turned over a significant amount of evidence and lab results to the EPA for further criminal action.


What We Do…


The Division audits the refineries to verify compliance with regulatory reporting requirements, analytical methodology and procedures used to analyze fuel quality. This helps the Division to ensure that the fuel being produced at the refineries meets both the regulatory and fuel quality requirements before it leaves the refineries. It is at this point the refineries certify the fuel as CBG.  During the past 4 years, the Division investigators conducted formal audits of all refineries that provide fuel to the state and found no instances of non-compliance with fuel quality standards for fuels delivered into the state.

Storage Terminal

This is an intermediate point where different batches come together before it is put into the pipeline. This is the point where the fuel becomes a fungible product (it loses its individual identify when it is mixed with other batches of CBG). The Division requires that the transfer of this fuel be tracked to ensure that the fuel is not mixed with anything other than the required CBG ingredients. In 2011, the Division conducted formal audits of the chain of evidence and traceability of fuel produced at the terminal, which is required to clearly state the contents of the fuel, and found no significant violations.


The Division requires that the fuel parameters be checked prior to entering the pipeline to ensure it meets federal and state requirements. A Quality Assurance program is also required to randomly check different suppliers fuel quality parameters. These parameters are then reported to the Division.  The Division maintains monthly oversight of this Quality Assurance program and the proprietary information and ensures requirements are regularly maintained, while communicating Arizona’s concerns on a regular basis.  No civil penalties or significant violations were discovered in 2012.

Distribution Terminal

After the long journey to the Phoenix or Tucson terminal the fuel is now ready to be distributed to the service stations in the area. In the case of wintertime fuel requirements (November 1 through March 31), the fuel must first be blended with up to 10% Ethanol which is done just as the fuel is loaded into the truck that will deliver it.  The Division requires the terminal to have a Quality Assurance program not unlike that of the pipeline. The terminal is required to take random samples from trucks at the loading rack to help insure that the level of ethanol will meet State requirements.  Every inspection for fuel quality conducted by Division investigators incorporates a thorough analysis of the Product Transfer Documents (“PTD”) which spell out the exact fuel content and specifications, as well as the destination and other chain of custody requirements.  Investigators regularly review these PTDs as maintained by transportation fueling trucks and inside each gas station.  In 2011, a distribution terminal was civil penalized in the amount of $195,000 for violations per the Department.

Fueling Stations

The last point at which the Division can ensure fuel quality is at the service stations.   On a daily basis, Division investigators randomly visit service stations collecting samples, checking equipment and conducting a number of other tests. As mentioned, the samples collected are taken to a laboratory to be analyzed.

Business Specifics

State law requires you to be a registered supplier and to follow specific laws and administrative rules relating to Arizona Cleaner Burning Gas (CBG) or Arizona Reformulated Blend Stock for Oxygenated Blending (AZRBOB) program. Here are some pages that may be of interest to you.

Compliance Assistance Program