Major increases in unemployment have spread from Michigan to other states in the Midwest, where workers now are exhausting unemployment benefits and moving the recession into a second, more serious stage.

According to a newly released study by the Bureau of Labor Statistics, the largest increases in unemployment in 1980 were in Michigan, Illinois and Indiana, where layoffs and closings in the auto industry and other manufacturing businesses kept boosting the figures.

Unemployment rates also increased sharply in adjacent Kentucky and West Virginia, according to the report. In contrast, in 1979 only Michigan -- where the ripples began -- registered a significant jump in unemployment.

Nationally, nearly 9 million persons are out of work, according to federal figures which some observers believe understate the size of the problem. Of that 9 million, 7.8 million still were looking for work, while another 1.1 million were counted as "discouraged workers" who want to work but who have given up looking out of despair.

Those figures are based on December unemployment report, which contains the latest available data. At that time, the national unemployment rate was 7.4 percent, but several major layoffs have occurred since then.

With the recession in the auto industry well into its second year, hundreds of thousands of workers in the Midwest have exhausted both their supplementary unemployment benefits and unemployment compensation payments, both of which initially cushioned the Midwest from the shock of massive joblessness.

"No one here officially calls it a depression, but most people refer to it that way unofficially," said Al Sandner, a spokesman for Michigan Gov. William Milliken.

In Michigan approximately 20,000 workers are exhausting their unemployment benefits each month, with many of them among onto welfare. At the end of 1980, some 265,706 workers had used up those benefits compared with 142,000 in the recession year of 1975. A record number of families are on welfare, with nearly 240,000 collecting aid for dependent children and another 97,000 collecting general assistance for individuals and couples without children.

"My income is zero. It's going to have to come down to welfare," said Dave Black, an auto worker in Utica, Mich., who had used up all his benefits Jan. 4, a year after he was laid off from his job as a maintenance welder at the Ford plant there.

"I had a couple of hundred dollars saved from unemployment and trade adjustment assistance," Black said.

I've been using that more or less to live on right now." He is looking for work, and his wife is studying to qualify for a secretarial job, but neither has any immediate prospect.

Unmarried friends have begun to talk about moving to Texas to find work, but Black, with two children and a three-year-old mortgage, isn't as free to move. And he is high enough on the seniority list to be tantalizingly close to being recalled to a job that previously paid him well.

Duane Duncan, who loaded bumpers at a Chevrolet plant in Livonia, Mich., has been out of work since September 1979 and used up his benefits nearly a year ago. Since then he has supported himself with odd jobs and some help from his parents. "I'm scarping, but it's enough," he said.

The worst part is when the weather gets bad and the odd jobs dry up.

In other states, as well, joblessness is beginning to seem more than a temporary phenomenon. Nationally, for the 12 months ended last September (the latest period for which the figure is available) 2,693 million workers had exhausted their regular benefits. In 25 states where unemployment is above 4 1/2 percent, jobless workers may collect benefits for another 13 weeks after they exhaust regular benefits.

"By this time in the recession of 1974-1975, a recovery was underway," said Don Stillman, a spokesman for the United Auto Workers. But no recovery seems imminent, especially in the increasingly depressed Midwest.

Because of continuing slow sales, U.S. automakers have announced plans to close 11 car and truck assembly plants next week, and long-term layoffs are increasing.

Major automakers had laid off 197,550 hourly workers indefinitely as of last week, the highest number since the week of Oct. 16, 1980. It was the sixth straight week in which indefinite layoffs increased.The UAW estimates that more than 250,000 of its members -- including people who work in auto parts manufacturing plants and other factories -- are out of work.

The closings announced this week will put another 24,150 workers out of a job for one to three weeks.