"They are upset with the fact they feel that an offer was made and they didn't get a chance to vote on it," Barker said.
Jason Miller, the union president, said union members expect the negotiating committee to speak for them.
"That's where they give the union committee consent to vote," Miller said in a telephone interview.
The union and the company differ on what happened just before the strike.
Constellium said that since negotiations began in May, the union has never made a counter offer.
The union's account differs.
Miller said the union made a counter offer before the strike Saturday.
"The company came back to the table on Saturday and we countered it and the company rejected it and we're on strike," Miller said.
A press release from the union does not describe any of the terms of that counter offer.
The company currently pays 100 percent of workers' insurance premiums, though employees do pay some co-pays.
The company offered wage bonuses to employees in exchange for being able to reduce long-term health care costs to the company by making workers pay 10 percent of insurance premiums in the final year of the 5-year contract.
Billy Thompson, a United Steelworkers director for a four-state region including West Virginia, said the strike was a "last resort."
"We hope that the company will sit down with us and work out a fair deal for everyone involved - one that helps them stay competitive without pushing more hard-working people into a race to the bottom," Thompson said in a statement.
The strike could be another blow to Jackson County, which lost 650 jobs in 2009 when Century Aluminum idled its plant in Ravenswood. The county has struggled to get back on its feet ever since.