By Teresa Carson
PORTLAND, Oregon (Reuters) - Portland teachers put Oregon's largest school district on formal notice Thursday that they intend to go on strike February 20, disrupting classes for nearly 48,000 students, unless the two sides reach agreement by then on a new contract.
Rank-and-file instructors in the 2,800-member Portland Association of Teachers voted overwhelmingly on Wednesday night to authorize union leaders to call a strike if talks collapse in a labor dispute centered on staffing levels and wages.
The district has said it already has contingency plans to keep its 78 schools open using substitute teachers in the event of a walkout.
Some parents, however, have expressed discomfort at the prospect of their children crossing picket lines to attend classes or extracurricular activities. Students at several Portland high schools staged walkouts from classes on Thursday to show support for the teachers.
The union set a deadline for February 20 at 6 a.m. local time (1400 GMT) for reaching a settlement on a new three-year contract but is required by state law to give the district at least 10 days notice before staging a strike.
Bill Wilson, chairman of the union's bargaining committee, said that formal notification was delivered to the district Thursday morning.
The next round of negotiations, to be conducted with assistance of a mediator, was set for Sunday, but Wilson said the union has offered to hold additional bargaining sessions on Thursday, Friday and Saturday.
"If they came over here today, we could get this done," union president Gwen Sullivan said. "Our hope still is not to go on strike."
Jon Isaacs, a senior policy advisor for the school district, said that the mediator had strongly advised both sides not to meet without her, and that Sunday is the next day she would be available.
"We are going to follow her advice," he said.
Isaacs said the mediator was currently preoccupied with a separate labor dispute that led teachers in the much smaller district of Medford, 270 miles south of Portland, to strike Thursday morning, idling some 13,000 students at 22 schools.
The Medford district reported that "significant movement" on salary and benefits was made in a marathon round of overnight contract talks.
Portland Public Schools spokeswoman Christine Miles said Wednesday night after the strike authorization that district officials were "deeply disappointed" but held out hope for making progress toward averting a strike in upcoming talks.
The union and school district have been at odds over class size, teacher workloads, wages and insurance coverage, but the issue of staffing levels has emerged as the chief stumbling block, according to union officials.
Pointing to a budget surplus projected for the coming year, the union is demanding that the district hire 176 new teachers, while the district wants to add 88 instructional positions and save more of its extra funds as a rainy-day reserve.
Isaacs said the two sides disagreed over whether "budget decisions belong in the contract." He said teachers also were opposed to a district plan for phasing out an early retirement program.
In the area of wages, teachers are asking for raises of 3.75 percent in the first year and 3.52 percent in the second year of the new contract. The district is offering a 2 percent salary hike for each of the next two years.
(Reporting by Teresa Carson; Editing by Steve Gorman)