Unison is campaigning for the dismissal of a trust chair who was part of a panel which planned to reinstate a paramedic team leader sacked for sexually harassing a young female colleague.
The union has told the Department of Health that it cannot work with Carlisle Hospitals trust chair Malcolm Bullough, and is calling for his dismissal.
And it is threatening all-out strike action if he is appointed as chair when the trust merges with West Cumbria Health Care trust.
The conflict follows the dismissal of Neil Marston by Cumbria Ambulance Service trust after managers ruled that he had sexually harassed two junior colleagues.
But last month a three-member appeal panel that included Mr Bullough overturned the ruling saying Mr Marston should be reemployed with a written warning, though it concluded that he was guilty of sexually harassing one of the women under his supervision.
The appeal panel recommendation was itself overturned by an emergency board meeting of the ambulance trust which followed intervention from senior DoH officials in London. The intervention came after staff made it clear they would take industrial action if Mr Marston was re-employed.
But the Cumbrian branch of Unison says the recommendation has outraged women and 'gives a green light to sexual harassers'.
Unison regional officer for Cumbria Peter Doyle said members were furious that the appeal panel allowed the two women involved to be asked a series of what they described as 'inappropriate' questions which included: Did you wear a skirt or trousers?
Did you cry? Did you practise safe sex? And, what form of birth control do you use?
It is understood that Mr Bullough asked the two questions about birth control and safe sex.
The panel also included two non-executive members of the ambulance trust - Fiona Cartmell, who retired last month, and solicitor Lorraine Greenwood, who chaired the panel.
The case prompted the union to call an emergency meeting of the representatives of the county's 150 ambulance staff, who unanimously condemned the appeal panel.
And a second meeting of Unison shop stewards resulted in a vote of no-confidence being passed in the panel.
Mr Doyle said: 'We view this as a serious case of sexual harassment. . . the recommendation to reinstate the man was unsafe.
'It sent out a clear message to sexual harassers saying it is OK to do it once - you will get away with a written warning.
'The questions asked were sexist and insulting. We have made it clear that we will refuse to cooperate with Mr Bullough and will walk out of any meeting. We are calling on the secretary of state to dismiss him.
'If Bullough is appointed as chair of the merged trust, which will have 4,000 women employees, we will consider industrial action.'
Mr Doyle said the original disciplinary hearing, chaired by ambulance trust chief executive Alan Donkersley, had acted properly to order Mr Marston's dismissal.
Mr Bullough said that it was inappropriate to comment because the dispute concerned individual ambulance trust employees. Ambulance trust chair Brian Clayton declined to comment for the same reasons.