Union workers at a Kansas plant of Duluth-based AGCO Corp. say they're still waiting for a response from the farm equipment manufacturer on what they call an unfair switcheroo that penalizes employees for taking sick leave.

The roughly 1,100 unionized employees at AGCO's Hesston, Kan., plant now get two marks —- or "points" —- each time they take one of the five sick days they are allotted a year. They also get one point for missing up to four hours of work or two points for missing more than four hours for other reasons.

After 16 points, employees are subject to termination, said Brian Lansaw, president of the United Steelworkers Union Local No. 11228, which represents the Hesston workers.

The attendance policy change, begun May 12, comes about seven months after the union ratified a three-year extension to its labor agreement, which already has a points system, he said.

Under the existing contract, workers are not penalized on the first three sick days taken and get one point for the fourth missed day of work.

"We could live with that," said Lansaw, who last month filed a grievance with the National Labor Relations Board. "Our attendance policy was a tough policy but a fair policy."

AGCO says it expects the issues to be resolved at the Hesston plant, the only unionized factory among its three U.S. operations. Each plant sets its own absenteeism rules, the company said.

"The AGCO Corp. has a long history of excellent relationships with the union in Hesston," Norm Boyd, the company's senior vice president of human resources, said in an e-mail statement. "We expect the current issues to be resolved to everyone's satisfaction in accordance with agreed-upon processes and look forward to continuing to expand the work force and capacity in this valuable facility. We will have no further comments on this until the resolution is finalized."

What the Steelworkers will have to prove to the NLRB is that the change represents a substantial difference from the contract, said Barry Hirsch, an economics professor and Usery Chair of the American Workplace, a center that studies labor trends at Georgia State University. "If you have some substantial change from what's in the contract, then you can't impose that unilaterally."

The union says the company made no reference to changing the policy until the contract extension was ratified.

Even if the new policy is different from the contractual agreement, it probably will be hard for the union to win, said John Trumpbour, research director of the Labor and Worklife Program at Harvard Law School.

"The argument you hear out there is a lot of companies don't have to fear a ruling against them if it goes to the NLRB because at the federal level it's very sympathetic to management's side," Trumpbour said. "That has emboldened a lot of companies to take a lot of liberties with contractual obligations."

The issue already has led to Hesston workers holding a lunchtime protest late last month.

The row comes as AGCO is undergoing an employment boom. The plant employs 1,459 and represents 53 percent of the work force among the company's three plants. The other two operations are in Beloit, Kan., and Jackson, Minn.

In the last 12 months, Hesston added 175 workers to make combines and hay equipment.

Lansaw, the union president and a 19-year plant employee, said he thinks the company is looking for a easy means to get rid of some existing workers as new ones come in.

"We're in the middle of a huge hiring frenzy," he said, "and the changes —- they're just making it easier to fire people throughout the course of the year."