WESTBROOK – Members of the largest union at Sappi Fine Paper’s Westbrook mill were voting on a new contract Tuesday, a day after workers at the larger Sappi mill in Skowhegan narrowly approved a labor agreement.

In Westbrook, the more than 170 members of Local 169 of the United Steelworkers have been working without a contract for more than four years. After the rank-and-file voted earlier this summer to authorize a strike, the company advertised for potential replacement workers.

Union President Brian Wade said the proposal being voted on Tuesday represents an improvement over the previous offer and he believes that the strike vote may have influenced management.

The contract approved Monday by workers at the Somerset mill in Skowhegan followed three years of negotiations. President Rod Hiltz of Steelworkers Local 4-9 said it allows for some wage increases but also includes unsettling cuts in retirement benefits.

“It was a very narrow acceptance,” Hiltz said. “This company has got a lot of work to do; a lot of people are unhappy.”

Union members at the Somerset mill, which has a work force of 900, did not authorize a strike.

Brooke Carey, a Sappi spokeswoman, said the company was pleased that the union ratified the contract.

“We are very much looking forward to working with the union and our employees under the new agreement and we are pleased to be moving forward,” she said.

Hiltz praised the endurance of union members during the long-running contract talks.