Union workers at a Cargill plant went on strike early Monday after rejecting a contract offer in Cedar Rapids.
The strike began at midnight Sunday with the third shift. The decision to strike came after nine hours of negotiating and voting.
"No one's every happy about striking," said Gary Dunham, principal officer of Teamsters Local 238.
Dunham said the 102 Teamsters at the plant objected to job-security provisions.
The union said about 18 union jobs at the corn-milling plant would have been replaced with nonunion, subcontracted jobs.
"(These subcontractors are) from different areas from around the state and out of state that come in here that are paid substantially less than some of our people that work at this particular plant," Dunham said.
Cargill, based in Wayzata, Minn., makes food ingredients.