Austin firefighters will likely begin to respond to medical and fire calls in Williamson County — and vice versa — in a year or two, according to a deal approved by Austin City Council on Thursday. The vote came after intense resistance from the Austin firefighters union, which for months has been urging the council to delay voting on the agreement until they could get Williamson County firefighters to agree to follow their protocols at fire scenes. Union President Bob Nicks said he is happier with the final version of the deal but he is still wary. The agreement the council approved still allows Williamson County departments to follow different procedures but it makes a commitment to eventually move toward one set of rules. “The Austin Fire Department is the largest urban department that hasn’t had a line-of-duty death in the past four years,” Nicks told the American-Statesman on Wednesday.