U.S. Environmental Protection Agency (EPA) Administrator Scott Pruitt enraged environmental groups on Thursday after saying in a television interview that he doesn’t believe carbon dioxide (CO2) emissions are a primary contributor to climate change.

Meanwhile, a high-ranking official within EPA’s Office of Environmental Justice tendered his resignation on Tuesday over reports that the Trump administration intends to make deep cuts to the agency’s budget.

Pruitt told Joe Kernen, co-host of the CNBC program “Squawk Box,” that “measuring with precision human activity on the climate is something very challenging to do and there’s tremendous disagreement about the degree of impact.

“So no, I would not agree that [CO2] is a primary contributor to the global warming that we see. But we don’t know that yet. We need to continue the debate and continue the review and the analysis.”

Although Pruitt’s comments on climate change appear consistent with his earlier views on the issue, they contradict statements posted on EPA’s website. Under the agency’s “Causes of Climate Change” section, EPA says CO2 “is the primary greenhouse gas that is contributing to recent climate change…

“Human activities, such as the burning of fossil fuels and changes in land use, release large amounts of CO2, causing concentrations in the atmosphere to rise.”

Environmental groups immediately condemned Pruitt for his comments.

“The arsonist is now in charge of the fire department, and he seems happy to let the climate crisis burn out of control,” said Sierra Club Executive Director Michael Brune. “As Pruitt testified before Congress, it is the legal duty of the EPA to tackle the carbon pollution that fuels the climate crisis, but now he is spewing corporate polluter talking points rather than fulfilling the EPA’s mission of protecting our air, our water, and our communities.”

Pruitt’s comments also appeared to rankle his predecessor, former EPA Administrator Gina McCarthy.

“The world of science is about empirical evidence, not beliefs,” McCarthy said in a statement, according to reports. “When it comes to climate change, the evidence is robust and overwhelmingly clear that the cost of inaction is unacceptably high. Preventing the greatest consequences of climate change is imperative to the health and well-being of all of us who call Earth home.

“I cannot imagine what additional information the administrator might want from scientists for him to understand that.”

During his confirmation hearing before the Senate Committee on Environment and Public Works last January, Pruitt testified that he believes climate change is real, saying “science tells us that the climate is changing and that human activity in some manner impacts that change.” But he also said there needed to be more discussion about climate change, especially over “the degree and extent of that impact, and what to do about it.”

Last month, Pruitt told EPA employees that he planned to withdraw the CPP. In an interview, he questioned whether EPA had the appropriate tools to regulate CO2 emissions, or if Congress has even authorized such regulatory power. Media reports showed Pruitt appeared to continue that line of thought at the CERAWeek by IHS Markit conference in Houston on Thursday, where he was a guest speaker.

In February 2016, the U.S. Supreme Court issued a stay blocking implementation of the CPP until all legal challenges to the plan were resolved.

On Tuesday, Mustafa Santiago Ali — the assistant associate administrator for Environmental Justice at the EPA and a 24-year employee at the agency — penned a three-page resignation letter to Pruitt.

“When I hear we are considering making cuts to grant programs like the Environmental Justice Small Grants or Collaborative Problem Solving programs, which have assisted over 1,400 communities, I wonder if our new leadership has had the opportunity to converse with those who need our help the most,” Ali wrote to Pruitt. “I strongly encourage you and your team to continue promoting agency efforts to validate these communities’ concerns, and value their lives.”

Last month, the Trump administration outlined a draft budget that envisions possible cuts to foreign aid and domestic agencies, including the EPA, in order to fund a $54 billion increase in defense spending. Reports speculate that the EPA could face a 20% cut in its workforce.