Most Detroit public schools closed on Monday for a “sick-out” in which teachers are protesting against funding levels for the school system.
Ninety-four of 97 schools in the 46,000-student district were closed for the day.
A union representing the district’s teachers urged them to call out sick because of dwindling funds.
The union says there is not enough money to pay teachers for the summer or for summer schooling.
The teachers protested poor working conditions in January, calling for another “sick-out”.
Many schools in the district are in disrepair, with mould, mildew, leaking pipes and unsanitary working conditions.
Michigan Governor Rick Snyder passed a law providing emergency funding for the district to stay open. The state legislature is considering a $270 million (£184 million) restructuring plan for the district.
It is illegal for teachers in state schools to go on strike in the state of Michigan.
The union’s interim president, Ivy Bailey, said in a statement that “by refusing to guarantee that we will be paid for our work, [Detroit Public Schools] is effectively locking our members out of the classrooms.”
As the BBC’s Sean Coughlan reported in February, the school closures are the latest stage in a dispute about pay and what teachers say are the terrible conditions in Detroit’s schools, with overcrowded, crumbling, unhygienic classrooms and chronic underfunding.
‘Sick outs’ staged by teachers banned from striking
“The gym is closed because half of the floor is buckled and the other half suffered so much rainwater damage from the dripping ceiling that it became covered with toxic black mould. Instead of professionally addressing the problem, a black tarp simply was placed over the entire area like a Band-Aid,” Lakia Wilson, a teacher the the district’s Spanish Elementary-Middle School, wrote in a blog post in January.
“How can you teach or learn in conditions like these?”
The number of students in the Detroit Public School system has fallen by about 80% compared with the 1970s.
Bankruptcy judge Steven Rhodes, who oversees the district, called the union’s “drastic call to action” unnecessary.
He called the sick-out “counterproductive and detrimental”.