Tom Dickerson is the president of SEIU Local 266 NCFO, which represents the union workers at the Fredonia and Dunkirk facilities.
"I've been watching this place. About September we said 'something's not right, they're going to shut us down.' We're watching things and doing everything and we've never met ConAgra until today. Never met them once.
"How I found out was a fluke. They sent a letter to our pension fund. Our president called me and said 'hey, they're not funding it after this date.'
"I said it's like I've been saying, I tried to warn people but I had no proof.
Dickerson said ConAgra will notify workers as their 90 days left to work comes up, eliminating the need to go through the states WARN site.
"They're going to phase this plant out. When one department is done they take the equipment and they ship it to Bucknor," Dickerson added. "I'll be trying to get these guys a severance package and some insurance, things like that. You've got 425 people, average age 47.
"I think they said around October will be the first of it, but they'll be out of here by the end of next February, but there will only be a handful of people when that happens."
Dickerson said the workers were "devastated."
"I went in there early this morning to let the people know what's going on because I didn't want them to walk into a situation where they were going to get kicked ... because they had no idea. Thank God for that fluke letter or we all would have. I went in and started telling people, they were devastated, their whole lives change. People in their late 40s and late 50s, they can't retire. They'll all be going on welfare.
More than 60 percent of ConAgra's plants are unionized, according to Dickerson, who added the closing will leave one ConAgra facility in New York state, Sugar Cakes in Tonawanda, a cookie plant.
Dickerson said ConAgra told workers the plant was closing due to low volume and the ability to produce products better at other places.
"They bought us to shut us down. They didn't put any money into the plant," he added.