EPA Advances DEF Proposal as WOTUS Review Continues

Officials say stakeholder input will help shape a new Waters of the U.S. definition.

WASHINGTON, D.C. (RFD News) — EPA is proposing changes to diesel exhaust fluid (DEF) power limits and emissions warranty requirements that agency officials say have increased costs for diesel users.

Scott Mason said the proposal would scale back emissions warranty requirements while maintaining the underlying emissions standards.

“I would also note that EPA is also specifically proposing to scale back the emissions warranty requirements that added the largest single cost to the trucking industry because truckers have been hampered by this just like farmers and ranchers. Under this proposal, the Trump EPA would then maintain the underlying emission standards, including nearly 90% of the nitrous oxide or NOx reductions while also sparing Americans from unnecessary warranty costs.”

The proposed rule would eliminate power limits tied to DEF warnings and is currently in a 45-day public comment period.

Beyond diesel regulations, EPA is continuing work on a new Waters of the U.S. definition. The agency has been holding listening sessions and roundtable discussions with stakeholders.

“We have had listening sessions and roundtable discussions on WOTUS for the last several months, and so our headquarters team is still working on that. Know that this agency will come up with a proposal that is durable, it is clear, it is concise, and it is in line with the Supreme Court’s decision on Sackett. We’re still working on it, but it will be something that follows the law and is clear and it is durable, it is in plain English. No longer will you have to determine if your stock tank, as I often like to say at my farm in western Oklahoma, is not a Waters of the United States.”

EPA says work on the proposal is ongoing.

Related Stories
Additional assistance is expected, but producers are encouraged to plan ahead.
Washburn University law professor Roger McEowen says the H-2A visa program follows a different federal payroll framework than domestic agricultural labor.
ASFMRA’s Chad Hertz also discusses farmland leasing strategies, common negotiation mistakes, and considerations for balancing rental income with long-term tenant relationships.
Tractor rental and application services saw the largest increases, with tillage, planting, harvesting, and spraying costs all rising sharply.
Watch whether higher livestock costs and uneven input prices continue squeezing 2026 returns.
Consumers may see moderate overall inflation while still facing large swings across meat, produce, and eggs.

Knoxville native Neal Burnette-Irwin is a graduate from MTSU where he majored in Journalism and Entertainment Studies. He works as a digital content producer with RFD News and is represented by multiple talent agencies in Nashville and Chicago.


LATEST STORIES BY THIS AUTHOR:

GreenLab says its GMO corn product produces brazzein, a natural sugar alternative that is 2,000 times sweeter than table sugar.
Proposal would allow certain facilities to limit drone flights as debate grows over security and oversight.
Industry officials say rainfall will be critical as harvest expands northward.
Harvest season marks another year of collaboration between the brewer and barley growers.
USMEF says increased purchases are creating new opportunities for American producers.
Analysts say spring wheat is trailing last year’s crop as record temperatures persist across parts of the Plains.