FORT WAYNE and KOKOMO - The United Auto Workers union, which totals approximately 49,000 workers at 33 General Motors Co. (NYSE: GM) plants nationwide, went on strike at midnight. The strike affects workers at GM plants in Fort Wayne, Bedford, Marion and Kokomo. The Fort Wayne plant, which assembles full-size pickup trucks, employs about 4,500 UAW workers. Our partners at WPTA-TV in Fort Wayne report several hundred were seen on the picket line throughout the day.

In all, about 7,000 UAW members work at the four Indiana plants. Union leaders from across the nation voted to strike Sunday after the collective bargaining agreement expired Saturday night.

“We stood up for General Motors when they needed us most. Now we are standing together in unity and solidarity for our Members, their families and the communities where we work and live,” said UAW Vice President Terry Dittes.

The autoworkers are calling on the Big 3 automaker to recognize the contributions and sacrifices they say the company’s UAW members have made to create a healthy, profitable, industry. The strike does not include Ford and Fiat Chrysler Automobiles whose contracts were extended indefinitely.

In an interview with Inside INdiana Business, University of Indianapolis Associate Professor of Finance Matt Will said he was surprised the UAW decided to strike.

"During a time when we have a contracting manufacturing base, which was indicated by last month's PMI numbers, it's kind of surprising that the UAW would kind of throw fuel on a fire of a possibly shrinking manufacturing segment of the economy right now," said Will. "Indiana is not heavily based on GM because, of course, we have Honda; we have Toyota; we have Subaru. Indiana is partially isolated from this particular strike."

Will says one area of concern is for the companies throughout the state that supply parts to GM. He says 58% of all the manufacturing for the automobile industry in Indiana is in the parts sector.

In a statement from GM, the company says “We presented a strong offer that improves wages, benefits and grows U.S. jobs in substantive ways and it is disappointing that the UAW leadership has chosen to strike at midnight tonight. We have negotiated in good faith and with a sense of urgency. Our goal remains to build a strong future for our employees and our business.”

The Kokomo Tribune reports 300 workers at the GM Components Holding plant are also on strike. That factory produces components, such as semiconductors, engine and transmission control modules, and diagnostics modules.

The Marion metal stamping plant employs about 900 workers and the Bedford castings factory employs about 750 hourly workers, according to the GM website.

“Our members have spoken; we have taken action; and this is a decision we did not make lightly. We are committed to a strong contract at GM that recognizes our UAW members, who make some of the greatest products in the world and make GM so profitable,” said Ted Krumm, chair of the UAW national bargaining committee.

The union striking points include fair wages, affordable healthcare, share of profits and job security. One of the big sticking points is announced closings of four GM factories in Michigan and Ohio. The union says it will fight the closures.

Will says the strike will play into ongoing fears of a recession, especially considering the country's trade disputes with China.

"That's why this is so surprising to me because of course manufacturing and big-ticket manufacturing will be the first area hit by a recession and a trade war," said Will. "So it's kind of illogical that the UAW would go after General Motors at this specific time when, let's suppose they win in the negotiations and there's a recession, then GM could be in not the same condition, but a similar condition to what they were in 2008: major financial struggles as a result of a recession and then having to go back to labor and say, 'Look, we need to renegotiate.'"