The head of the Environmental Protection Agency on Wednesday defended his decision to repeal the legal determination that serves as the basis for federal rules to slow climate change, telling a gathering of climate change skeptics they should “celebrate vindication.”

EPA Administrator Lee Zeldin made the remarks in the keynote address at a conference hosted by the Heartland Institute, a conservative think tank that rejects mainstream climate science and what it calls “climate alarmism.” Zeldin told the gathering that repeal of the 2009 “endangerment finding” reversed decades of unthinking adherence to liberal politicians and environmental groups about the dangers of climate change.