(CBS News) CHICAGO - Chicago's 25,000 public school teachers went on strike for the first time in a quarter-century Monday, after the latest contract talks broke down Sunday with no deal to avert a walkout.
Chicago Teachers Union President Karen Lewis said late Sunday night there had been some progress in contract talks, but "we have failed to reach an agreement that will prevent a labor strike."
The city's public school teachers make an average of $71,000 a year. Both sides said they were close to an agreement on wages. What apparently remains are issues involving teacher performance and accountability, which the union saw as a threat to job security.
Late Sunday, Mayor Rahm Emanuel, who has already forced teachers to lengthen their school days, said he was "disappointed" in the union's decision to continue with a strike.
"I am disappointed that we have come to this point, given that even all the other parties acknowledge how close we are because this is a strike of choice," Emanuel said. "Because of how close we are, it is a strike that is unnecessary."
After talks ended last night, Chicago Board of Education President David Vitale said he believes CPS officials made their best possible offer to teachers.
"There's only so much money in the system. There's only so many things that we can do that are available to us," Vitale said. "At this juncture, it is clearly their decision. ... We've done everything we can."
Lewis said the two sides were close to agreement on a contract, but not close enough.
"We are not far apart on compensation, however we are apart on benefits," Lewis said. "We want to maintain the existing health benefits."
Lewis said the union is also concerned that a proposed new teacher evaluation system "could result in almost 6,000 teachers - or nearly 30 percent of our membership - being discharged within one or two years. This is unacceptable and leads to instability for our students."
She said the new evaluation system would rely too much on students' standardized test scores.
"This is no way to measure teacher effectiveness at all," she said.
The union has planned a 3:30 p.m. rally on Monday outside Chicago Public Schools headquarters.
A dispute involving public sector employees in Chicago was somewhat surprising, said CBS News correspondent Dean Reynolds, given the generous packages unions here have won in the past. In addition, a teacher strike in the hometown of a president who stresses the importance of education could also be seen as something of a political embarrassment.
The union had set a midnight deadline for a walkout. Negotiations are to resume on Monday at 10 a.m. at a secret location.
Teachers began to walk picket lines at schools shortly before 6:30 a.m., and students and parents were left looking for alternatives.
Chicago Public Schools is opening about 140 schools for children from 8:30 a.m. to 12:30 pm.; however, no instruction will take place.
About 45,000 students who attend the city's charter schools will not be affected by the walkout - their schools will stay open.
In addition, churches, libraries and community organizations will be providing students with activities.
That is a worry for many parents.
"I have some concerns about who is going to be taking care of my kids, if the child-to-adult ratios will be too high," Tiffany Williams told CBS station WBBM.
Police Superintendent Garry McCarthy said the police department is also putting more officers on the street to deal with potential protests, and children who might not be in school.