DANVILLE — More than 240 workers at Danville’s Viscofan USA began a strike Friday. The plant at 915 N. Michigan Ave., makes casings for food products.

According to Kevin Dawson, vice president for human resources at the plant, workers rejected the company’s latest contract offer. The two sides have been in negotiations since January, according to a release from United Food and Commercial Workers Local 686, which represents the workers.

The company and workers are negotiating a three-year labor agreement, according to Dawson, which includes wage increases, a plant efficiency plan that pays a monthly performance bonus and a signing bonus of $1,000 upon ratification of a new agreement.

The union release says the company’s offer includes no wage increases for the first year; new, mandatory overtime requiring workers to come into work at a moment’s notice; additional mandated on-call time for maintenance workers; and new, random and intrusive drug testing.

“The men and women of Viscofan work hard to produce the high-quality products that have made the company successful,” said UFCW Local 686 President Tim Miller in the release. “They have earned and deserve the better wages they need to support their families. When a company like Viscofan succeeds, its workers and the communities they serve should succeed as well.”

“We are disappointed that the offer was rejected by the union,” Dawson said in the company’s release. “We hope that this labor dispute will be short lived. Meanwhile the company has implemented its’ contingency plan to keep servicing the market.”

Viscofan, headquartered in Spain, generated nearly $2 billion in revenue last year, according to the union release.