Union workers at Duferco Farrell Corp. have ratified a new four-year contract under which workers get a pay hike in return for paying higher medical insurance co-payments.

Members of United Steelworkers Local 1016-03 ratified the contract last week, said Dave McLaren, president of the local. He declined to give a vote count. The local represents about 400 production and maintenance workers at the Farrell steel plant.

“The only thing left is for us to clean up misspelled words in the contract and correct some grammar,’’ McLaren said.

Negotiations between the company and union dragged on for more than nine months as wages, benefits and health care were the main sticking points.

“It was tough, that’s for sure,’’ McLaren said of bargaining talks.

Terms of the contract, which expires in April 2012, call for workers to get a total of $3.40-an-hour wage increase over the life of the contract. The increase represents about 4 percent a year, McLaren said.

On the flip side, workers are required to increase their medical insurance contribution to cover between 20 to 25 percent of the cost under the new contract compared to 17 percent under the old contract, he added.

Other terms call for workers to get an additional holiday, Good Friday, along with an increased company contribution in the pension plan. One change under the new contract is that the work week will begin on Sunday instead of Monday. The change benefits laid-off workers receiving unemployment compensation, McLaren said.

A Duferco representative did not return a phone call Thursday afternoon.

Layoffs are running high at the plant as more than 50 percent of union workers are currently laid off, he added.

The steel industry was humming along until mid-summer when, like the rest of the economy, the downturn began to hit, he noted.

“A bunch of those workers will be coming back next week which will bring the percentage under 50 percent,’’ McLaren said. “I wish the vote would have meant that everyone gets to come back to work right now but that’s not going to happen.’’