"As an expert on pesticides, he helped design new regulations to improve food safety," Bush said. "In his new role, Steve will lead federal efforts to ensure the security of our drinking water supply."
Johnson has been with the EPA for 24 years. The agency has 18,000 employees and an annual budget of over $8 billion.
Bush said administration policies were helping cut emissions from heavy duty vehicles and were helping restore abandoned industrial sites to productive use. He called on Congress to pass his Clear Skies initiative to reduce power plant pollution.
Johnson is a graduate of Taylor University in Indiana and obtained a master's degree in pathology from George Washington University. Prior to joining the EPA, he had worked as director of operations at Hazelton Laboratories Corporation and Litton Bionetics, Inc.
Celebrity Breakups and divorces of 2014 [PHOTOS]