Unionized workers at Merck & Co. Inc.'s Montgomery County plant, where the drug company is making its new cervical cancer vaccine and other key products, have ratified a three-year contract containing a no-layoff clause.

In a statement today, the United Steelworkers said 70 percent of members of Local 10-86 voted for the contract on Monday. The Steelworkers union, which absorbed the former chemical workers union at the plant, represents roughly 1,800 of approximately 10,000 employees at Merck's huge West Point complex.

Merck did not comment on the new pact, which will replace one that expires tomorrow.

The union said Merck, under the contract, has pledged "no layoffs" of union members at West Point. The company made the promise while it is slashing positions and outsourcing work worldwide, although it also has said no cuts were planned in West Point.

On one contentious issue, the union also said the company has agreed to eliminate time clocks in its West Point facilities "on a trial basis." Instead, employees will log hours themselves, it said.

The contract "will help to maintain seniority rights for our local members. It enhances our wages and other benefits. And it will go a long way towards solidifying the position of the West Point facility within Merck," Charles Fickert, the local union president, said in a statement.

The union said its members would receive each a $4,500 "signing bonus" and a 3.5 percent raise in 2007, 2008 and 2009. It said Merck also agreed to increase its contribution toward medical benefits for the USW members by $4.5 million immediately, and by an additional 11 percent each year of the agreement.

"The result is that it's unlikely any USW member will pay more for medical insurance for the life of the contract, a significant benefit at a time of skyrocketing health insurance costs," the union said.

It said the new pact provides an "improved benefit and pay package" for workers who choose to retire early and assures "premium pay" for any time worked over 40 hours a week. It also creates a full-time union safety representative.

The pact takes effect as Merck tries to recover from troubles stemming partly from its 2004 recall of painkiller Vioxx. Its cancer vaccine and new diabetes treatments helped Merck's share price rise last week to its highest, $52.63, in more than three years.

It was down roughly 1 pecent, or 62 cents, to $50.81, in trading today.