TORONTO (AP) – Ontario gingerly reopened for business Monday, with subways and streetcars running in Canada’s largest city for the first time since last week’s huge blackout.

Not everyone went back to work. The government offered only essential services and authorities urged consumers to halve normal electrical use so the system can cope with the strain of restarting after a power outage Thursday that plunged eight U.S. states and parts of Canada’s most populous province into darkness.

Officials said Ontario’s power system was several days from returning to full strength.

“We are going to have to get the cooperation of not just industry and the retail sector but the public throughout the week,” Premier Ernie Eves said Monday. He warned that hot, clear weather expected this week would heighten the demand for power.

Ontario has the capacity to supply 20,000 megawatts Monday compared with the 23,000 megawatts or more it normally uses on a hot summer weekday, Eves said. At 9 a.m., the demand was at 16,500 megawatts, about 1,500 less than a usual Monday in the summer.

Several large companies – including automakers DaimlerChrysler and Ford – said late Sunday they would comply with the requested 50 percent cutback. DaimlerChrysler shut down an assembly plant and two research labs in Windsor, while GM Canada said it halted production at its Oshawa, Ontario, plants.

The cutbacks resulted in far fewer people than normal heading downtown in Toronto for the start of the work week.

“You can shoot a cannon down some of these streets,” said bus driver Jack White, a 22-year veteran of Toronto’s public transit system. “They’ve done a really good job scaring people.”

At a midtown subway station, proprietor Saratha Bala shook her head when asked about business at her kiosk selling candy, drinks, newspapers and other items.

“Summer is usually bad, but this is really, really bad,” she said, gesturing at the trickle of commuters walking past.

Eves asked people to use major household appliances including washing machines between 8 p.m. and 8 a.m., to wash clothes in cold or lukewarm water and to forgo air conditioning.

The 125th Canadian National Exhibition, an annual two-week fair known for its rides and neon lights, delayed opening until Tuesday. It had been scheduled to start last Friday, the day after the blackout.

Bruce Campbell, vice president of the Independent Electricity Marketing Operator that regulates Ontario’s power, said the province can import power, as it did Saturday when it received help from Manitoba, Quebec, New York and Minnesota to prevent rolling blackouts.

Toronto officials decided to restore public transit, which carries more than 1 million people a day, despite the possibility of new blackouts Monday.

The Canadian Bankers Association said banks across the province would be open for business but would turn off electric signs and curtail air conditioning.

Eves complained that Canada was not notified about problems occurring in the interconnected power system ahead of the blackout, as required by a protocol established after a severe blackout in 1965.

The cause of Thursday’s blackout is unclear but investigators have focused on a utility company in Ohio, FirstEnergy.

According to a preliminary analysis, FirstEnergy was experiencing unusual “electric conditions” as much as four hours before the blackout.

hit Thursday.

“After the famous 1965 blackout, North American protocols were established to ensure that interconnected jurisdictions are notified immediately when problems develop in one province or state on the grid,” Eves told reporters at a Toronto news conference.

“For some reason, that did not happen this past Thursday,” he said.

Eves insisted the blackout was not linked to the fact that Ontario – in contrast to most summers in the past – has been importing power from the United States instead of exporting it.

He said Ontario should remain a part of the North American electricity grid while also developing new infrastructure that would make it self-reliant.

AP-ES-08-18-03 1604EDT