Workers at Cenveo’s envelope plant in Westmoreland County rejected the company’s contract proposal for a fourth time Thursday, lengthening a rancorous labor dispute in which the rank and file has lobbed as many salvos at its union as at the company.

The proposed three-year contract was voted down 146-119, according to John Haney, who has worked at the plant 35 years and is the former president of the United Steelworkers union local there.

The proposal would have covered about 330 employees at the plant, which is on the site of factories formerly operated by Volkswagen and Sony. Stamford, Conn.-based Cenveo bought the business for $25 million in cash and stock in 2013 after the previous owner filed for bankruptcy for the second time in three years. Mr. Haney, 59, said workers continue to work under the terms of a contract that expired Sept. 14.

Thursday’s ballot also included a vote on whether to strike, a notion that workers also rejected, Mr. Haney said.

When Cenveo took over, workers agreed to a 5 percent pay cut.

The company’s proposed contract would have restored the pay cut, about 60 cents an hour, in the first year of the contract and provided for 25-cent-per-hour increases in the second and third years. A provision requiring workers to work 40 hours a week before collecting overtime instead of being paid overtime after working an eight-hour day also upset union members.

Mr. Haney said union workers are paid from $12 to $20 an hour under the former contract.

The rank and file’s biggest gripe with USW officials is that Thursday marked the third time they were asked to vote on a contract they had rejected on two previous occasions, including the most recent vote taken Saturday.

They also rejected an earlier contract offer.

“They want us to vote yes so it’s over with,” Dontay Stokes, 41, said of union officials. “They’re taking our [dues] money and basically telling us to shut up.”

He said 69 members rejected the contract proposal in Saturday’s vote while 54 voted in favor of it.

USW District 10 supervisor Bobby “Mac” McAuliffe said a new vote was called because a large number of workers complained they could not make it to the polls on Saturday. One excuse was hunting season, he said.

“There were a ton of different excuses about why they couldn’t come in to vote,” Mr. McAuliffe said.

Mr. Haney called the explanation “bunk.” He said some workers didn’t vote because they were angry at being told to vote on a proposal they had already turned down.

“I think they just look down on us,” he said of USW headquarters.

Other workers were upset that USW staff representative Linda Breeden referred to the rank and file as “nasty people.”

“I’d like to see her work for $12 an hour and make a living,” worker Diane Siecinski said.

Ms. Breeden tells a different version of the story. She said each contract put to a vote contained a few sweeteners that the previous version did not have. The latest proposal includes an incentive clause that could boost pay by up to 11 percent, she said.

“They keep bringing up new issues,” Ms. Breeden said of members. “We’ve sort of exhausted everything we could get from the company. ... There’s just not much more to go back to get.”

Calls to Cenveo seeking comment were not returned.

An earlier version of this story incorrectly identified a worker at the plant. The worker's name is Dontay Stokes.

First Published: December 11, 2015, 5:00 a.m.