For most of the University of California system, the last week of classes for the spring quarter begins today. But it’s likely to be disrupted on a number of campuses.

A strike by U.A.W. 4811, the largest employee union in the University of California system, that began at one campus on May 20 is expected to expand to three more this week — two of them today.

In all, the union represents 48,000 graduate teaching assistants, researchers and others at 10 U.C. campuses and the Lawrence Berkeley National Laboratory. Its members voted last month to authorize a strike to protest the university’s response to campus demonstrations over the Israel-Hamas war and what they say are unsafe work conditions and violations of free speech rights.

The first campus the union struck was U.C. Santa Cruz. The work stoppage spread to U.C.L.A. and U.C. Davis last week. This week the union plans to add U.C. San Diego and U.C. Santa Barbara on Monday, and U.C. Irvine on Wednesday, raising the total number of strikers to as many as 31,500.

The growing strike may complicate matters for the more than 169,000 undergraduate students at those six campuses as they wrap up instruction and take final exams. (The remaining campuses are U.C. Riverside and U.C. San Francisco, where classes are still in session, and U.C. Berkeley and U.C. Merced, which are on the semester system and finished in May.)

“How can our campus claim to be a beacon of free speech when those of us who stand in our quad saying ‘Free Palestine’ suffer serious injuries that prevent us from doing our jobs?” Elliot Yu, a U.C. Irvine graduate worker, said in a video posted on social media by the union.

In the video, he said that he was arrested at a campus protest and that zip-tie cuffs injured nerves in his hands. He said he had been barred from the U.C. Irvine campus, where he not only works but also lives.

“We can’t allow these unfair labor practices to go unanswered,” Yu said in the video. “Until the U.C. changes course and resolves the unfair labor practices that have led to this crisis, more and more workers will be prepared to stand up.”

The union said that dozens of academic workers were facing criminal or disciplinary charges related to protests at U.C. Irvine, U.C.L.A. and U.C. San Diego, and that the union’s primary demand was that those charges be dropped.

University of California officials say that the strike is unlawful because it’s not related to labor issues, and that the union is trying to pressure the system to concede to a political agenda. The university system tried to get the state Public Employment Relations Board to seek an injunction against the strike in court. The request was denied, but the board issued a complaint accusing the union of failing to provide adequate notice of its work stoppage, and failing to meet and confer with the university in good faith.

In a statement on Friday, the U.C. Office of the President said that the union had created “substantial and irreparable impacts on campuses.”

“We are disheartened that U.A.W. continues publicly escalating its unlawful strike in violation of its contracts’ no-strike clause and encouraging its members to disrupt and harm the ability of our students to navigate finals and other critical year-end activities successfully,” the statement said.

Soumya Karlamangla is a reporter with The New York Times. Copyright 2024, The New York Times.