The return of bitter cold and a worsening of the natural gas shortage combined yesterday to make Ohio the hardest-hit state in the union in the current energy crisis.

Ohio Gov. James A. Rhodes declared an energy crisis and all schools served by Ohio's four ultilities will be closed today and as many as 250,000 workers may be off their jobs as Ohio attempts to shift a limited supply of natural gas from factory to home use, state officials said.

School and factories in the Ohio River Valley, including portions of Kentucky, Indiana, West Virginia and Pennsylvania as well as Ohio, were also being closed as zero temperatures hardened the ice on the river and blocked heating oil and kerosene deliveries to communities from Pittsburgh on the east end of the river to Louisville in the west.

Factory layoffs in Ohio went up from 75,000 to more than 100,000 last night as the state's largest natural gas pipeline cut back deliveries at midnight to its largest customers. Glass plants closed in Toledo and Lancaster, and automotive factories shut down in Dayton and Brookpark outside Cleveland.

Snow fell yesterday in Cleveland, and temperatures fell all over Ohio, with forecasts of sub-zero temperatures for the Ohio River Valley, where temperatures have run 20 degrees below normal all winter. Schools in Marietta, Lancaster and Zanesville closed yesterday with instructions that water be drained from their pipes to prevent them from freezing and breaking.

Just when schools will re-open was unclear last night, since there was little chance the natural gas shortage would end soon, or that the weather would warm up or that the ice in the Ohio River would thaw to let barges move heating oil and kerosene into communities needing them.

Factories still open last night said they did not know how long they could stay open since they did not know if they could resupply themselves with the bottled gas and heating oil they were burning instead of natural gas.

Owens-Illinois laid off 900 workers last night at two glass plants in Toledo and Columbus, where natural gas is used as a clean source of regulated heat near the end of the glass-making process. It said it had no more than a 10-day supply of bottled gas to run a third plant employing 1,800 workers. Libby-Owens-Ford laid off 800 workers at its East Toledo plant because of the natural gas shortage.

General Motors laid off 6,000 workers at four of its plants in Dayton, where GM makes brake linings, steering wheels, shock absorbers and refrigerators.

Ford Motor Co. said it was laying off workers at its Brookpark plant, but did not say how many. Ford indicated that layoffs could run as high as 25,000 by Monday.

Elsewhere in Ohio, greenhouse operators were being forced to reduce their use of natural gas to warm the vegetables and flowers growing in an estimated 5,000 greenhouses across the state. Greenhouses produce 80 per cent of the tomatoes grown for the Cleveland market.

"This is the hardest year I've ever seen for the greenhouse industry," said John van Wingerden, a greenhouse operator outside Cleveland. "Fore can shut down for three weeks and start right up again, but if we close for three hours, we're done."

Ohio River Valley communities were among the hardest hit, despite being in the southern part of the state. Factories in Marietta, Zanesville, Portsmouth, Lancaster and Ironton were all closed last night.

Many Ohio River Valley communities are allocated natural gas on the basis of historical weather patterns, but this winter temperatures along the Ohio River have averaged 10 degrees colder than cities and towns in northern Ohio.

There was little shortage of natural gas in the river city of Cincinnati, where Cincinnati Gas & Electric Co. began to curtail gas customers as long ago as Nov. 1 and where factories laid in big supplies of bottled gas and heating oil to stay open.

Therefore, when schools were closed for one week in Cincinnati it was due more to heavy snows than gas shortages. The frozen Ohio River was more of a problem for Cincinnati. The city's supply of salt to melt the ice on city streets was still sitting last night on barges stuck in the river ice.

Downstream, in Louisville, residents were told yesterday to run at least one water faucet in their homes to keep pipes from freezing. The ground around Louisville was frozen to a depth of 30 inches and the Louisville Water Co. said it had taken more than 10,000 reports of frozen pipes from its 200,000 customers.

Lousiville had largely escaped the natural gas shortage until last night, when seven factories laid off an estimated 3,000 workers. The largest layoffs took place at the Naval Ordnance plant, Tube Turns and the American Standard Co., which makes sinks and bathroom fixtures.

In both Ohio and neighboring Indiana, the governors lifted all restrictions on burning coal and high sulfur oil. Ohio Gov. Rhodes called for a day of prayer to end the fuel shortage, but state school Superintendent Martin Essex predicted that most schools in Ohio would be forced to close next week because of the worsening gas shortage.

"The situation is very critical," Essex said, "and I guess that's the understatement of the winter."