The head of the Nuclear Safety Commission is accusing Natural Resources Minister Gary Lunn of improper interference with the agency.
And in a letter to Lunn, Linda Keen warns that she'll sue over any attempt by the minister to have her fired.
Keen issued a caustic reply Tuesday to a letter Lunn sent her late last month, in which he threatened her termination for refusing to follow a ministerial directive.
"Any objective assessment of the facts will reveal that the allegations contained in your letter are entirely without merit,'' Keen wrote in her eight-page reply, posted on the commission website.
Lunn's letter, and comments made by the minister during a Dec. 8 telephone conversation "are examples of improper interference with both the institutional independence of the CNSC and with the administration of justice,'' said Keen.
The federal Conservative government and the commission have been at odds since last fall, when the 50-year-old nuclear reactor at Chalk River, Ont., was closed for safety upgrades.
Keen maintains Atomic Energy Canada Limited, and not her agency, made the decision to extend the shutdown of the reactor to complete the upgrades.
Lunn and Prime Minister Stephen Harper publicly criticized Keen after she insisted the reactor remain closed until a backup safety system was installed. The shutdown cut off the bulk of the world's supply of medical isotopes, stalling critical diagnoses and treatments.
Lunn wrote to Keen in a letter dated Dec. 27, questioning her judgment and her abilities to continue as president of the agency. He told her he was considering recommending her dismissal to cabinet.
That letter will have a negative effect on other quasi-judicial agencies that are supposed to be at arm's-length from government, Keen predicted.
"I (am) deeply troubled by both the tone and content of your letter,'' she wrote.
"I would therefore ask you to carefully consider the significant chilling effect your recent actions could have on the practices and decisions of other tribunals who are responsible for important work on behalf of Canadians.''
Before the government forced a restart of the Chalk River reactor with special legislation, the nuclear watchdog was insistent that a backup safety system be installed to eliminate the remote risk of a core meltdown during an earthquake or other disaster.
A spokesperson for Lunn defended the minister's letter Tuesday.
"It is now appropriate for the government to examine the options at its disposal to address the underlying issues that led to the situation in the first place,'' Louise Girouard said in an e-mail to The Canadian Press.
Keen has asked the privacy commissioner and the RCMP to investigate how Lunn's letter was leaked to the media.
The Mounties would not confirm Tuesday that they received the request for a probe, nor would they say whether an investigation would be opened. The privacy commissioner's office would only say it was aware of the complaint.
Keen was appointed to her current position in 2001 and is in her second five-year term. She had previously worked at provincial government agencies and with the federal Agriculture Department.
In light of Lunn's letter, the Sierra Club of Canada called on Parliament to protect the Nuclear Safety Commission from political interference. It insisted the watchdog be granted powers of independence similar to those given superior court judges and the auditor general.
"The safety of Canadians is threatened when our Nuclear Safety Commission is subject to the kind of bullying the minister has demonstrated,'' said Stephen Hazell, the Sierra Club's executive director.
The Liberals accused the Conservatives of using Keen as a scapegoat to cover up their inept handling of the medical isotope crisis.
And the NDP called Lunn's threat another example of Harper's government putting partisan politics above good governance.
"If there is anyone that Canadians have lost faith in, it would be this minister,'' said Catherine Bell, the NDP Natural Resources critic.
She added that Lunn's intimidation tactics would affect all regulators who might be forced to choose between public safety and reprisals from political masters.
If Keen was intimidated by Lunn's threats, she wasn't showing it Tuesday, seemingly daring the minister to prove she did anything to warrant dismissal.
"I am advised that (I) cannot be removed from the office of president without cause,'' she wrote. "There are no grounds upon which an objective reviewer would conclude that cause exists in my case.''
The Nuclear Safety and Control Act states that permanent members of the commission can only be removed for cause, and that only permanent members of the commission can hold the office of president.
It's not the first time the Tories have threatened the tenure of a government agency office holder.
Adrian Measner was fired in December 2006 as president of the Canadian Wheat Board over his public opposition to Conservative plans to end the Winnipeg-based agency's monopoly on barley sales.
Previous governments also got into heated political and legal battles after summarily getting rid of top Crown agency executives.
Jean Pelletier, once a top aide to former prime minister Jean Chretien, won a court battle last March over his dismissal as head of Via Rail.
Former Liberal prime minister Paul Martin fired Pelletier for making disparaging remarks about former Via employee and Olympic biathlete Myriam Bedard.
But a Federal Court judge ruled Martin's government acted improperly in 2005 when it fired Pelletier a second time after a court overturned his first dismissal.
