Fuel Cost Relief Measures Create New Questions for Truckers, Farmers, and Equipment Owners

Users Should Understand Fuel Requirements Before Changing Fueling Practices

Washington, DC, Oct. 13, 2026 (GLOBE NEWSWIRE) -- Rising diesel fuel prices are increasing costs for freight transportation, agriculture, construction, and other essential industries. In response, federal and state policymakers have introduced temporary measures intended to provide economic relief, including changes affecting diesel fuel taxation and fuel use requirements. While these actions may offer short-term savings, they also create concerns about the negative impacts of high sulfur levels and the risk of misfuelling certain diesel engines and equipment that will cause performance, maintenance, warranty and other problems.

“Temporary relief measures may help reduce operating costs, but diesel users should not assume that all diesel fuels are interchangeable,” said Allen Schaeffer, executive director of the Engine Technology Forum. “Understanding which fuel is appropriate for a particular engine and complying with tax and regulatory requirements can help avoid equipment damage, unnecessary maintenance costs, warranty concerns, and compliance issues.”

For many trucking fleets, farms, construction firms, and equipment operators, fuel represents one of the largest day-to-day operating expenses. As policymakers explore ways to reduce those costs, users should carefully evaluate both the potential savings and the operational implications of any fuel-related changes.

Federal Relief Measures

Ultra-low sulfur diesel (ULSD) remains the standard diesel fuel used throughout the United States for both highway and nonroad applications. Highway and nonroad ULSD share the same fuel specifications for sulfur (a maximum sulfur content of 15 parts per million (ppm)). The primary distinction is tax treatment: highway diesel is subject to federal highway fuel taxes, while nonroad diesel is exempt from those taxes and is dyed red to support enforcement efforts. ULSD is suitable for use in diesel engines of all ages and remains the required fuel for modern diesel engines equipped with advanced emissions-control technologies.

A recent federal Executive Order temporarily allows the use of red-dyed, nonroad ULSD in highway vehicles through December 31, 2026. This measure may reduce the immediate impact of the federal highway diesel fuel tax, currently $0.244 per gallon. However, questions remain regarding tax treatment, enforcement, and whether taxes will ultimately be waived or deferred pending additional guidance from the U.S. Department of the Treasury.

State Requirements Vary

In addition to federal taxes, all states and some local jurisdictions impose their own diesel fuel taxes. Several states have implemented temporary relief measures permitting the use of red-dyed diesel fuel in highway vehicles under specific conditions. However, eligibility requirements, enforcement provisions, and expiration dates vary significantly from state to state. Diesel users should carefully review the rules governing when and where they purchase fuel and where their vehicles operate.

Texas and Alaska Fuel Waivers Require Additional Attention

Diesel fuel users operating in Texas should be particularly aware of recent regulatory changes. Texas has received a U.S. Environmental Protection Agency (EPA) waiver allowing fuel sold in 110 counties to meet a less restrictive sulfur specification than normally required under the state's Texas Low Emission Diesel (TXLED) program. Under the waiver, diesel fuel with sulfur levels of up to 500 ppm may be sold temporarily in affected areas. Truckers and other fuel users should note that this waiver does not exempt them from applicable Texas fuel taxes.

The Texas waiver affects fuel specifications only and should not be interpreted as authorization to use higher-sulfur fuel in engines that require ULSD.

EPA also granted a waiver for Alaska, where the use of diesel fuel up to 5,000 ppm sulfur is permitted until October 24, 2026.

Understanding Engine Compatibility

Using fuel that exceeds the 15-ppm sulfur limit in newer diesel engines can damage diesel particulate filters, catalysts, and other emissions-control devices, potentially leading to costly repairs, increased maintenance requirements, and warranty concerns. Customers should verify fuel compatibility before making any fueling changes and consult their engine, vehicle, or equipment manufacturer or dealer if questions arise.

Most on-highway trucks beginning with the 2007 model year emissions standards utilize advanced emissions-control technologies that require ULSD. Likewise, most Tier 4 nonroad diesel engines require ULSD and may not use higher-sulfur fuel permitted under the Texas waiver. Older highway and nonroad engines certified before these standards may be able to operate on higher-sulfur fuel under the conditions outlined in applicable waivers. Owners should confirm engine certification levels by reviewing the emissions label located on the engine.

EPA Warning Remains in Effect

EPA has specifically warned that the use of diesel fuel exceeding the 15-ppm sulfur standard in vehicles or equipment equipped with diesel particulate filters or catalytic emissions-control devices may cause significant engine and emissions-system damage. Operators who choose to use higher-sulfur fuel assume responsibility for any resulting equipment damage and may face additional maintenance requirements.

Proceed Carefully During a Period of Change

Additional questions regarding federal, state, and local tax enforcement remain unresolved, including how compliance will be evaluated both during and after these temporary relief measures expire. The continued presence of red dye in fuel systems after temporary orders end may also create compliance concerns for some operators.

“The current fuel-price environment has created understandable interest in cost-saving opportunities,” Schaeffer said. “But regardless of temporary policy changes, diesel users should confirm fuel compatibility before making changes that could affect engine performance, emissions systems, warranties, or regulatory compliance.”

For more information, visit enginetechforum.org.

Allen Schaeffer
Engine Technology Forum
3016687230
etf@enginetechforum.org