FOXBOROUGH — Unions representing thousands of Stop & Shop workers in Massachusetts and Rhode Island are voting to authorize a strike if a contract dispute with the supermarket chain drags on.

Members of Local 328 of the United Food and Commercial Workers' union voted unanimously in favor of the authorization Sunday in Foxborough, Massachusetts. Three other UFCW locals have also voted to authorize a strike. Another chapter representing Stop & Shop workers, Local 919, is slated to meet later Sunday.

The contract dispute centers on health insurance, pensions and vacation time. The union says Stop & Shop is looking to "degrade the quality of life" of workers.

The supermarket chain says it's offered proposals that "would ensure full-time associates continue to be among the highest paid food retail workers in the region."