Thomas D'Agostino, the Department of Energy under secretary responsible for Hanford environmental cleanup, is leaving the federal government, he announced Friday.
His last day will be Jan. 18, when Neile Miller, the principal deputy administrator for DOE's National Nuclear Security Administration, will step in as the acting under secretary.
In a memo Friday, he said the decision to leave had been difficult. But the end of the first term of the Obama administration is the right time for him to step down after 36 years of federal government employment, the past five and a half as under secretary for nuclear security, he said.
"I am a strong believer that organizations are healthier when leadership changes on a periodic basis," he said.
D'Agostino has been in charge of DOE environmental cleanup programs since a DOE reorganization by Energy Secretary Steven Chu in summer 2011.
The DOE Office of Environmental Management, which is responsible for Hanford, was moved under the direction of the under secretary for nuclear security, who also is the administrator for the National Nuclear Security Administration.
Daniel Poneman, the deputy energy secretary, said during a visit to Hanford in July that environmental cleanup of former nuclear weapons sites like Hanford was a logical fit and allowed expertise to be aligned with NNSA, which is responsible for the nation's nuclear weapons and nuclear nonproliferation.
However, the move raised concerns, including from Rep. Doc Hastings, R-Wash. The change was made without consulting Congress, the states or communities with interests in environmental cleanup sites, he said.
He said the change put environmental cleanup of Hanford and other DOE sites at risk of becoming a lower priority.
In a memo Friday, Energy Secretary Steven Chu praised D'Agostino's work in environmental management and nuclear security.
Under D'Agostino's watch, the Office of Environmental Management has cleaned up 690 square miles of contaminated land across the nation, Chu said.
"But programmatic accomplishments are just one way to determine his value to the department," Chu said. "The truest measure is the commitment and professionalism of the men and women he leads, and the trust the president and I have shown in his judgment and vision."
D'Agostino made his first visit to Hanford in September 2011, discussing Hanford vitrification plant issues -- saying he had a bias for action because of the risk of leaving untreated radioactive waste in underground tanks -- and saying he wanted to see unneeded land at Hanford reused.