Rick Vermeulen cools off with a drink from his water cooler, taking a break from the 95 degree heat, Thursday, July 21, 2011, in Bay City, Mich. Vermeulen and his crew from ATT are building a new manhole on Midland Street.

Cincinatti ? Hot weather that has plagued the Plains for days spread eastward Thursday, blanketing several more states under a sizzling sun that made people sick, shut down summer schools and spurred cities to offer cooling centers and free swimming.

The temperature could soar to 101 in Toledo, Ohio — 2 degrees above a record set in 1930. Combined with the humidity, it could feel as hot as 115 across Ohio.

“It feels very sultry, very uncomfortable, and it’s just very dangerous,” said Jim Lott, lead forecaster for the National Weather Service office in Wilmington, Ohio.

Government forecasters issued excessive heat warnings for a huge section of the country, from Kansas to Massachusetts, while some southern states were under heat advisories.

Thursday shaped up as the hottest day of a steamy week in Ohio, with temperatures climbing to 97 in the southwestern part of the state. Farther east, the worst of the heat waited for Friday and the weekend.

Scattered deaths have been blamed on the heat nationwide. The Ohio Health Department said emergency room visits have been three or four times higher than usual this week, mainly due to heat exhaustion and heat stroke cases.

Thousands of homes and businesses in southern Michigan lost power Thursday morning as people cranked up air conditioner use. Ferndale Recreation Director Julie Hall said a cooling center in suburban Detroit took in numerous senior citizens after their nearby apartment lost electricity.

Lisa Blumentritt headed to the cooling center after spending Wednesday night without air conditioning in an apartment where it was “difficult to breathe.”

Jackson, Mich.-based Consumers Energy asked its 1.8 million customers to try to reduce their electricity use by raising thermostats a few degrees, limiting opening of refrigerator doors and turning off unnecessary lights and appliances.

Baltimore, Annapolis and several other Maryland cities opened public cooling centers for folks to find relief. Allentown, Pa., waived fees at all public pools.

The temperature approached triple digits in Philadelphia and much of central and western New York. Philadelphia school officials sent students home early Thursday and canceled summer school for Friday.

In South Carolina, a heat index expected to spike Friday at 115 sent people to the beach and water parks.

“Traditionally what we see is that once July 4th comes, there’s a tapering off as people get back from vacations and get ready to go back to school,” said Phil Macchia, director of operations for Charleston County parks. “So far, we haven’t seen much of that, and the weather is a big factor.”

Some outdoor events also were canceled, but the annual Dayton Air Show said it would go on this weekend.

At the Warren County Fair in Lebanon, Ohio, rides were closed early Thursday afternoon. Fair officials pushed their opening time back to 4 p.m. because of the heat. Attendance is off this year, too, fair officials said.

“It’s miserable,” said Peggy Vanderpool, 52, working outside to park cars at the fair. “This is the worst year in the 10 years I’ve been coming here. Even the young kids are not handling it well.”

She said workers took regular breaks, drank plenty of water and wrapped wet rags around their necks Thursday to earn their $9 an hour.

At the Ottawa County Fair near Toledo, 14-year-old Austin Schimming hosed down his beef cattle and put on his jeans and button-down shirt for the calf judging.

“It’s worth it when the check comes,” the youth said of the hot clothing.

In Delaware, Ohio, a Harry Potter costume party fundraiser was moved from Friday to July 29. The party will benefit a group that seeks to preserve and promote downtown Delaware.

The statement from Main Street Delaware reported: “We blame nargles. (And the stifling heat, too).”