(CNN) EPA Administrator Andrew Wheeler said access to clean drinking water worldwide is "the biggest environmental threat," while climate change threats are "50 to 75 years out" in an interview with CBS on Wednesday.

While speaking at the Wilson Center later that day, Wheeler said he has become frustrated with the "current dialogue around environmental issues" because water issues often "take a back seat."

"Up to 2.5 billion people around the world lack access to safe drinking water and, as a result, proper sanitation. This fact leads to anywhere from 1 to 3 million deaths every year," he said in his remarks at the Wilson Center.

Wheeler pledged to "do more to address these issues" and said he believes the administration can focus on the clean water crisis "while still addressing other challenges that loom on the horizon."

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