EPA Has Renewed a Texas Waiver Allowing Higher-Sulfur Diesel Through Dec. 3 for Certain Older Engines

A temporary federal waiver that lets refiners and distributors sell diesel with a higher sulfur content in Texas takes effect today and runs through Dec. 3. In a Nov. 10 letter to Gov. Greg Abbott, EPA Administrator Lee M. Zeldin renewed an emergency fuel waiver that temporarily lifts the federal ultra-low sulfur diesel standard of 15 parts per million and Texas' state-implementation-plan low-emission diesel requirement, known as TXLED. The letter allows diesel to be distributed and sold with a sulfur level up to 500 parts per million. The waiver covers 20 days, which EPA's fuel-waivers page describes as the maximum allowed under the Clean Air Act.

EPA's fuel-waivers page says the agency, in consultation with the U.S. Department of Energy, issued a prior Texas diesel waiver on Oct. 20 that was effective through Nov. 13. The Nov. 10 letter says the new waiver is effective Nov. 14 through Dec. 3, and that EPA intends to issue new waivers extending the relief "until such time as the extreme and unusual fuel supply circumstances described in this action are no longer present."

The waiver does not open higher-sulfur diesel to every engine in the state. Zeldin wrote that refineries can produce low-sulfur diesel (less than 500 parts per million sulfur) for highway vehicles produced prior to the 2007 engine model year and for nonroad equipment with engines produced before the start of the Tier 4 emissions standards. A footnote says most 2007 model-year on-highway trucks will have 2006 model-year engines that can use the fuel under the waiver, and that the engine model year and Tier standard can be confirmed from the emissions label. Nonroad engines certified to Tier 1, 2, or 3 may use the fuel; Tier 4 engines may not and must continue to use ultra-low sulfur diesel.

The letter lists four conditions. The waiver is limited to highway and nonroad vehicles and equipment originally certified for low-sulfur diesel (less than 500 parts per million sulfur). The non-ULSD fuel may not be used in any diesel-powered highway or nonroad vehicle or equipment equipped with a diesel particulate filter or catalytic emission-control technology. It must be segregated from any fuel sold or labeled as ultra-low sulfur diesel. And anyone distributing or dispensing it must warn operators that using diesel above the 15-parts-per-million sulfur standard in a vehicle or engine with a diesel particulate filter or catalytic emission-control device "MAY CAUSE SERIOUS DAMAGE TO THE VEHICLE/ENGINE AND ITS EMISSIONS CONTROL COMPONENTS," that the user "ASSUMES ALL RESPONSIBILITY FOR DAMAGE," and that higher-sulfur fuel may require high-TBN engine oils and more frequent oil changes. The letter tells operators to consult the engine supplier on maintenance intervals.

The waiver applies only to the federal sulfur and TXLED requirements cited in the letter. Parties must still comply with other applicable requirements in 40 C.F.R. Part 1090. "Other state or local requirements or restrictions related to this matter may need to be addressed by the appropriate authorities," Zeldin wrote. Fuel that meets the waiver conditions and was already introduced into domestic pipelines, or certified at a manufacturing or import gate, before an element of the waiver expires may still be sold until the volume on the product-transfer documents or certificates of analysis is depleted.

The Nov. 10 letter responds to a Sept. 28 request from Abbott under Clean Air Act section 211(c)(4)(C)(ii). The governor asked EPA to waive the ultra-low sulfur diesel requirements in 40 C.F.R. section 1090.305 and the Texas Low Emission Diesel requirements in 30 Texas Administrative Code section 114.312, so that ultra-low sulfur diesel, or non-ULSD if otherwise waived, could be substituted in the 110 counties listed in section 114.319. Abbott wrote that diesel prices in Texas had reached an all-time high in September 2026 at $5.97 a gallon, citing the American Automobile Association as of Sept. 26, and that he had issued a disaster declaration for all 254 Texas counties because of rising fuel costs. That $5.97 figure is from the governor's request letter; this report has not independently verified current pump prices.

EPA's letter, issued with the Energy Department's concurrence, frames the problem as "extreme and unusual fuel supply circumstances" that could not reasonably have been foreseen and are not attributable to a lack of prudent planning by fuel suppliers. Zeldin wrote that global energy markets have been disrupted by Iranian attacks against tankers transiting the Strait of Hormuz and strikes against oil and gas infrastructure across the Middle East, as well as lowering U.S. refining capacity. Citing the Energy Information Administration, the letter says that in the first half of 2025 the strait averaged 20.9 million barrels per day, about 20 percent of global petroleum-liquids consumption, and that despite the strait's reopening last month, the EIA does not expect the majority of shut-in crude production to be back online until the first quarter of 2027.

On domestic supply, the letter says that as of the week ending Oct. 30, 2026, U.S. refinery utilization was 94.5 percent, above the seasonal five-year average, leaving refiners with "minimal ability to produce more refined products, such as ULSD." As of the same date, it says, national distillate inventories had fallen 12 percent below the five-year average and are not expected to recover to historical norms until early 2027. Nationwide operable crude capacity at U.S. refineries was 490,000 barrels per day lower in December 2025 than in January 2019, the letter says, citing EIA data.

Zeldin wrote that, after weighing the societal benefits of a higher volume of diesel being made available and the limitation of that fuel to engines originally designed for low-sulfur diesel, EPA concluded the waiver is in the public interest. The letter says Texas is the smallest geographic area necessary to address the circumstances described. It does not guarantee that refiners will produce the higher-sulfur fuel, or that pump prices will fall. The waiver allows that fuel to be made, moved, and sold in Texas under the conditions above, for 20 days, unless EPA renews it again.