DEF Technology Remains Essential Part of Emissions Compliance Strategy - Premature Intervention Could Disrupt Thoughtful EPA Guidance

ALEXANDRIA, Va., July 10, 2026 /PRNewswire/ -- NATSO, representing truck stops and travel centers, and SIGMA: America's Leading Fuel Marketers, questioned the Environmental Protection Agency's (EPA's) proposal to fundamentally alter the regulatory backdrop for diesel exhaust fluid (DEF) before the Trump Administration's previous, thoughtful Guidance documents are implemented and the benefits realized.

"Allowing ample time for existing Guidance to penetrate the market will minimize unnecessary and punitive deratements for diesel vehicles while ensuring that Selective Catalytic Reduction technology remains an essential part of every truck manufacturer's investment and compliance strategy," said David Fialkov, head of government affairs for NATSO and SIGMA. 

EPA's proposal would eliminate deratement as a mandatory inducement to satisfy NOx emissions requirements beginning in Model Year 2029. 

This proposal will invite consumer confusion and threatens to decrease DEF's availability and increase its price. There is no reason to undermine the common sense measures the Administration has already taken.

Prior to this proposal, the Trump Administration initiated a series of actions that — when fully implemented — can resolve consumer concerns surrounding diesel exhaust fluid and the operational reliability of DEF-related equipment. NATSO and SIGMA strongly support those efforts. The first Guidance documents issued in 2025 and early 2026 call for large-scale DEF software updates, the use of NOx sensors instead of urea quality sensors, as well as adjustments to the power reduction schedule. This is precisely what the market needed, but it takes time for the industry to realize the benefits: fewer false warnings and unnecessary repairs, and fewer situations where a functioning truck is unnecessarily taken out of service. 

"While the Administration's impatience is understandable, we believe it is counter-productive to prematurely disrupt that process when allowing it to proceed would negate the need for today's DEF-related actions," Fialkov said.

DEF remains an essential product for the reliable operation of commercial trucks regardless of whether EPA mandates that trucks derate. OEMs seeking to comply with EPA's emissions targets have integrated the use of DEF into the overall fabric of today's system designs. 

"The widespread adoption of DEF technology represents perhaps the most significant environmental success story for liquid fuels in the trucking sector," David Fialkov said. "It is an important demonstration that emissions reductions can be achieved through targeted innovation within the existing liquid-fuels framework."

NATSO and SIGMA support the benefits that DEF and SCR technology have delivered to emissions reductions and fuel economy. NATSO and SIGMA look forward to working with EPA to ensure that any further reform efforts are carefully targeted and evidence-based to avoid diminishing DEF's availability or increasing its costs for consumers.

About NATSO and SIGMA:

NATSO is the trade association representing America's travel center and truck stop industry. Founded in 1960, NATSO represents the industry on legislative and regulatory matters; serves as the official source of information on the diverse travel center, truck stop and off-highway fuel retail industries; provides education to its members; conducts an annual convention and trade show; and supports efforts to generally improve the business climate in which its members operate. For more information visit NATSO.com. Follow NATSO on Facebook; Instagram; LinkedIn; and X. Contact: Tiffany Wlazlowski Neuman, Vice President, Public Affairs. 202-365-9459

SIGMA is the national trade association representing the most successful, progressive, and innovative fuel marketers and chain retailers in the United States and Canada. Founded in 1958 as the Society of Independent Gasoline Marketers of America (SIGMA), SIGMA has become a fixture in the motor fuel marketing industry. Representing a diverse membership of approximately 250 independent chain retailers and marketers of motor fuel, the association serves to further the interests of both the branded and unbranded segment of the industry while providing information and services to members. For more information visit SIGMA.org.

CONTACT: Tiffany Wlazlowski, [email protected] 

SOURCE NATSO, Inc.