Members of a union representing research and technical workers walked picket lines Wednesday at University of California campuses and hospitals in a one-day strike amid a lengthening stretch of unsuccessful contract negotiations.
About 10,000 members of University Professional and Technical Employees-Communications Workers of America were expected to take part statewide, spokesman Dan Russell said.
They perform jobs including running clinical trials, assisting in laboratory tests, managing classroom technology and caring for research animals.
Vermont Sen. Bernie Sanders, who is again seeking the Democratic presidential nomination, addressed strikers at the University of California, Los Angeles.
"What we are seeing all across this country is a war being waged against the working people of America," Sanders told a rally.
"It is a sad state of affairs when people who work at this university cannot live in this community because they cannot afford to buy housing or pay the rent," he said.
The union and the University of California have been at odds since 2017 over issues including pay, health care premiums and retirement terms.
UC spokeswoman Claire Doan characterized the strike as "organized theatrics."
"Three disruptive strikes in less than one year come at a cost to everyone — patients, students and UC communities — while doing nothing to help unionized workers get closer to a contract and wage increases," Doan said in a statement.
The American Federation of State, County and Municipal Employees, which represents more than 25,000 patient care technicians and services in the UC system, said members were joining UPTE in a sympathy strike.
Doan said agreeing to the unions' demands would cost the UC hundreds of millions of dollars over the life of the contracts and would be unfair to other UC employees.
Union officials characterized the strike as a protest of growing income inequality at the university.
"For over a year, the University of California has continued to ignore the well-founded concerns of the workers that make this the finest research institution in the world," Jamie McDole, president of UPTE-CWA Local 9119, said in a statement.
The UC system includes 10 campuses, five medical centers and three national laboratories. It has 190,000 faculty and staff and 238,000 students.