Unifor Local 1359 representing 54 paramedics in the Sault says a strike now appears inevitable.
The deadline for a strike is midnight tomorrow and the union says city officials walked away from the bargaining table.
A main sticking point is wages and Unifor Local 1359 says the city is proposing increases of just half a percentage up from an initial offer of a quarter percent per year.
The union wants to see wage improvements that mirror agreements with other Unifor paramedic units.
Following four days of conciliation, Unifor says it was prepared to negotiate around the clock to reach a deal before the deadline of midnight tomorrow.