More than two dozen employees at a large warehouse on Staten Island were suspended by Amazon after they refused to work their shift the previous night because of a fire in a cardboard compactor.

The paid suspensions will last while an investigation takes place, according to a company email to the employees that was shared by the Amazon Labor Union.

Dozens of employees gathered in a break room to discuss fire safety and refused to work. The air at the warehouse may not be safe to breathe because of smoke or fumes.

The company said that it respected employees' rights to protest but that occupying work spaces was not appropriate.

Employees have a right to protest a dangerous work environment under federal labor law. An unfair-labor-practice charge would be filed by the union.

Night-shift workers were told by their supervisors that they would have to work despite the fire earlier in the day, even though some of them had been on the job.

The vice president of the Amazon Labor Union said in an interview that workers would like to go home. The day shift was sent home but the night shift was staying. Mr. Palmer is working the day shift.

After the fire department certified that the building was safe, night employees were asked to report to work. A small group of employees refused to return to work and stayed in the building without permission.

Some employees went to the main office to continue their protest, while others went back to their workstations, according to the union's treasurer.

The results of the union election on Staten Island have been challenged by Amazon. The workers at the Albany warehouse will vote next week on joining the Amazon Labor Union.