Nuclear Regulatory Commission chairman Gregory Jaczko yesterday announced his resignation from the body responsible for oversight of 104 nuclear power plants in the United States, including the embattled San Onofre Nuclear Generating Station in northern San Diego County.

The sudden announcement came amid months-long allegations that Jaczko had acted arrogantly toward other commission members and was particularly aggressive toward women during his term. His resignation comes in advance of an anticipated report from the Commission Inspector General’s Office addressing colleagues’ complaints.

“This is the right time to pass along the public safety torch to a new chairman who will keep a strong focus on carrying out the vital mission of the Nuclear Regulatory Commission,” said Jaczko in a statement released Monday. He will stay on in his position until a new chairman is confirmed by the Senate.

Controversy surrounding Jaczko’s tenure was dying down when Senate Majority Leader Harry Reid (D-NV) asked the White House not to re-nominate Republican Kristine Svinicki, a Jaczko critic, to the Commission. His suggestion was ignored, and President Obama went forward with the nomination.

Jaczko was in California last month, touring the San Onofre facility and meeting with plant officials and anti-nuclear activists, to whom he promised a “tough review” of the plant before giving the green light to restart operations. Earlier this month, he responded to suggestions from plant operator Southern California Edison that a plan could soon be presented for resuming power generation by calling any such actions “clearly premature.”

“Chairman Jaczko was the only NRC commissioner pushing to enact all of the lessons learned from the Fukushima tragedy,” said Rochelle Becker of nuclear watchdog group Alliance for Nuclear Responsibility. “[He] also recognized that NRC decisions often result in billions in costs to SCE and SDGE ratepayers and encouraged state action.”