Several hundred workers at the Twin River Casino and Event Center in Rhode Island are threatening to go on strike after their employer switched them to a more costly health care plan.

Twin River changed health coverage to a different plan offered by the same company in January without collective bargaining. The workers union says the move violates federal fair labor practices.

Jenna Karlin, vice president of the union, says union members are paying higher deductibles, co-pays and out-of-pocket costs. The premium for family coverage rose to about $12,000 a year, and union members say some deductibles increased more than a hundred percent.

A Twin River spokeswoman says the casino does not comment publicly on contract negotiations.