Around 50 American Red Cross workers in Lansing have returned to work after an 11-week strike.
Teamsters Local 580 spokesperson Lynne Meade says strikers failed to get more health plan options from the agency.
"They want to take away our right to agree or disagree with the plans that are being offered," she says.
A Red Cross spokeswoman says multiple plans are available, but all of them cost workers more.
The Red Cross is not obligated to submit to arbitration over the issue because the union's working under an expired contract.