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.

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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.


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