(CNN) William Ruckelshaus, a key figure in the Watergate scandal and the first head of the Environmental Protection Agency, died in his sleep Wednesday, his daughter, Mary Ruckelshaus, told CNN.

EPA Administrator Andrew Wheeler reacted to the news, saying in a statement, "The entire EPA family mourns the loss," and calling Ruckelshaus the "father of the EPA."

"Thanks to his leadership, all Americans are living with better air quality, water quality, and a cleaner and healthier environment," Wheeler said. "I am grateful for his service to the agency. My thoughts and prayers are with his family and loved ones during this time of grief."

Ruckelshaus started at the EPA during the agency's inception in 1970. As administrator, he guided the EPA through the enactment of the first federal environment statutes, steps that would define the agency's place within the federal government.

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