"I would say that curing cancer is going to be much more difficult when there's so much climate change and pollutants in the environment," she said.
The discussion moved on before Behar could explain the statement.
The hosts were discussing former Vice President Joe Biden's 2020 pledge to cure cancer. "That's why I've worked so hard in my career to make sure that... I promise you if I'm elected president, you're going to see the single most important thing that changes America, we're gonna cure cancer," Biden said on Tuesday.
Behar, on Wednesday, also decried how President Trump rolled back protections for the environment. "This president rolls back anything that will clean the air. They're working against each other if they don't also clean up the emissions."
Co-host Meghan McCain, whose father died of cancer, noted that it was unclear what caused brain cancer. McCain argued that every candidate should have curing cancer at the "forefront" of their platforms.
Biden also lost his son to brain cancer in 2015. He led a "cancer moonshot" program in 2016 and created the Biden Cancer Initiative after he left the White House.
As the race for the Democratic presidential nomination heated up, Biden and Trump offered some sharp attacks on each other on Tuesday. The president, for example, called Biden "mentally weak" while the former vice president labeled Trump an "existential threat to America."