Environmental Protection Agency Administrator Lee Zeldin delivered a keynote speech Wednesday at a conference hosted by the Heartland Institute, an organization that has disputed mainstream climate science.

Speaking at the Washington D.C. event, Zeldin criticized what he characterized as "bad, flawed assumptions" in favor of "accurate, present-day facts." The comments appeared to reference established climate science that forms the basis for federal environmental regulations.

Zeldin also defended his agency's decision to repeal legal determinations that serve as the foundation for federal rules aimed at addressing climate change. He told attendees to "celebrate vindication" regarding their skeptical views on climate policy.

The Heartland Institute has been a prominent voice questioning climate science and policy responses. The organization previously drew criticism in 2012 for billboard campaigns that compared climate advocates to violent extremists.

Zeldin's appearance at the conference signals a shift in EPA leadership approach toward climate science and environmental regulation. The administrator's remarks align with broader administration efforts to reconsider federal climate policies established in previous years.