The University of Massachusetts is laying off roughly 450 Resident Assistants and Peer Mentors — 95 percent of the staff — and will leave many without benefits and compensation the parties agreed to in a collective bargaining contract, according to multiple members of the RA/PM Union, which represents the student workers.

The decision comes in tandem with the school’s scale-back of its fall reopening plans. In a Thursday evening email, Chancellor Kumble Subbaswamy announced that only those in “essential face-to-face classes” would be able to live on campus, in addition to some others who rely on campus housing.

On Thursday afternoon, in anticipation of Subbaswamy’s upcoming announcement, an employee in UMass’ Labor Relations Office informed a union representative that the school would need to “withdraw its offer of employment” to most of the 500 student RAs and PMs.

In a meeting Friday afternoon between members of the union and Labor Relations representatives, the students were told that only 21 RAs and two PMs would keep their jobs for the coming semester in order to manage the limited number of students that would now live on campus.

UMass does not intend to pay the RAs or PMs it dismisses, said James Cordero, one of the union’s co-chairs. He said this is in violation of a contract the parties agreed to Wednesday, which entitles the workers to full compensation and benefits in the event that they’re laid off.

But the school holds that the RAs and PMs were not officially hired, said Patrick Burke, a union representative. Instead, UMass claims that members of the union were given “appointment offers” — not formal positions.

This isn’t the case, Cordero said. “We were literally placed in the ‘hired bin’ in their online employment system,” known as eRezLife.

In the Friday afternoon meeting, UMass Labor Relations representatives informed the union that only students who are dependent on campus housing and dining, including international students and those with on-campus classes, will be permitted to live on campus.

A portion of those students — the 21 RAs and two PMs — will keep their jobs. Those who aren’t given employment will still receive the cost reduction for dorms normally given to the staff and will be given priority to be rehired if more positions open up, the school representatives said.

Laid-off students who are dependent on campus housing, including those with difficult home-life circumstances, can apply to the Residential Life Student Services Office to be given a dorm, the Labor Relations representatives said. No timeline was given for how long that process would take.

The school’s decision comes just days before RAs and PMs were expected to move into their dorms and begin job training for the fall semester. Some were scheduled to fly into the country next week.

Now, many of those students face tremendous uncertainty, not only about whether they have a paying job for the semester, but also about whether they’ll have a dorm on campus when they arrive.

“Many people (myself included) were depending on the housing for the semester,” Erin Crowell, a senior communication major, who was set to be an RA this year, said via text. “Students who were already out in Amherst for the summer, intending on moving in next week, now have only days to find new housing plans.”

The school’s decision to only consider 23 of the students as officially “hired” is adversely affecting the many people who depended on this job as a significant source of income.

“A lot of us quit our jobs specifically to return to campus,” one union member said during the meeting with the school. As another put it, “Everyone’s an RA for one reason or another.”

It is not yet clear which, if any, other UMass employees will be affected by Thursday’s decision. Other staff, from maintenance and custodial workers to dining hall employees, will likely see decreased workload from a lower on-campus population.

“Pretty much every worker on campus will be affected by this,” Cordero said.

“This reversal is probably in the interest of public health,” he added, referring to UMass’ decision to cut back on the number of students living on campus. “We were against reopening, but it’s not an ‘either/or.’ It’s not either UMass takes care of its workers, or it stops the COVID outbreak.”

Crowell offered a similar sentiment. “I think the school made a good decision but didn’t consider the impacts it had on students fully, especially student workers.”

Will Katcher can be reached at [email protected] and followed on Twitter at @will_katcher.