Ambulance workers could take more strike action in a dispute over patient safety and union recognition.
Members of the Unite union staged a 24-hour strike at Yorkshire Ambulance Service (YAS) on April 2.
Unite called around 450 members out on strike after bosses de-recognised it for negotiations on behalf of its members.
The union had claimed patient safety was being put at risk by plans to send semi-skilled emergency care assistants to 999 call-outs.
YAS bosses have insisted safety will not be compromised.
The union’s Terry Cunliffe said: “Our offer to hold talks with the trust’s senior executives has been met by a stone wall of silence, which the Yorkshire public may find surprising given that the key issue here is patient safety.
“Our members want a resolution, but not at the expense of patient safety. To achieve this means addressing the underlying issues which are the derecognition of Unite and discussing the workforce plan.
“Our members will be holding meetings during the next week and, depending on what the consensus is, further strike action could be on the cards.”
Talks were held between the two sides over Easter but failed to stop the strike.
A YAS spokeswoman said: “These discussions, including face-to-face meetings, led to no change in Unite’s stance. They were unwilling to cancel their planned industrial action and did not agree to exempt key frontline staff from participating in the strike.
“For an ambulance service trade union to state that it is taking action in the interests of patient safety and yet to withdraw the labour of around 90 members of staff as part of the industrial action is further evidence of its unconstructive approach which led to the Trust ending its voluntary recognition of Unite.”