Ambulance staff will walk out on strike as a bitter dispute over changes to shift patterns rumbles on.
Members of the Unite union will stage two six-hour strikes on Friday an Monday from 3pm to 9pm.
Unite, which represents almost 400 workers, said Yorkshire Ambulance Service had “snubbed” the union’s attempts during the summer to hold constructive talks.
Terry Cunliffe, Unite regional officer said: “The trust’s chief executive David Whiting continues to play hard ball with his employees and has snubbed every genuine attempt by Unite to engage in positive talks for the benefit of the Yorkshire public.
“Our members firmly believe that the public deserve a first-class, fully resourced ambulance service - and, as they have shown on a number of occasions since April 2013, they have been prepared to strike to strongly make that case.
“We have been buoyed up by the support we have received from Yorkshire people - and we thank them for that. Unite’s door is open for talks under the auspices of Acas at any time.”
A number of strikes have been held during the past 20 months after the two sides could not reach an agreement.
Unite claims its members will go ten hours without a meal break and be forced to work 12-hour shifts by changes to working patterns introduced last month.
Mr Cunliffe said: “It is only a matter of time before someone is seriously injured or killed as a result of staff exhaustion.”
Ian Brandwood, Executive Director of HR at the Yorkshire Ambulance Service NHS Trust, said he was “disappointed” that the union had announced further strike action.
He added: “Once again the industrial action will take place without any concessions for the most seriously ill and injured patients and we remain concerned over this type of action.
“We would like to reassure members of the public that we have robust contingency plans in place. We continue to focus on safeguarding patient care and are committed to minimising the level of disruption to our services.
“Throughout the period of industrial action we will be taking steps to maintain operational cover to sustain effective and safe services for our patients who find themselves needing emergency medical assistance. We will continue to make every effort to get to patients as quickly as possible, whilst maintaining high standards of patient care.”