Employees at the Vancouver Art Gallery have gone on strike over a wage dispute with museum leaders. 

Members of the union CUPE Local 15 have been in negotiations with the museum, which is the fifth-largest in Canada, since a previous labor contract expired in June 2017. On Monday the union advised members to reject the latest proposal, dismissing the offered wage increases as “below inflation,” according to a statement.

Grant Arnold, a curator of British Columbian art at the museum, told ArtNews that the staffers saw strike action as a last resort, but felt they had no choice. “The frustration that precipitated the strike has been building for quite some time,” he said. “The gallery’s employees are very dedicated to their work—it’s been almost 40 years since they last went on strike.”

The employees are objecting to what they say is an unacceptable system for wage increases and a nine-day fortnight plan that would allow workers to pack two weeks’ worth of hours into just nine days.

“The gallery very much values its unionized employees and appreciates all their contributions,” a spokesperson for the museum told ArtNews. “There has been no rollback of benefits for its current team members and, in fact in many cases, benefits have been enhanced.”

The Vancouver Art Gallery staff are the latest among North American museum workers going on strike over working conditions, following walkouts of employees at New York’s Museum of Modern Art this past summer, and at New York’s New Museum last month. The strikes have attracted significant scrutiny to the pay and working conditions of cultural workers in the museum sector.

According to the Vancouver Sun, the museum has remained open to the public since the walkout started on Tuesday, though some services, such as events and tours, have been cancelled due to the staff shortage.