Updated

Michigan's governor urged residents to stay calm as she declared a state of emergency amid the continuing blackout Friday, while in Cleveland, workers filled "water buffalo" tanker trucks to ease the Ohio city's worst water crisis in history.

The outage was also responsible for a small explosion at the Marathon Ashland refinery  (search) about 10 miles south of Detroit, Melvindale Police Chief Sam Pedron said.

No one was injured, but police evacuated one mile around the 183-acre complex and sent hundreds of residents to seek shelter elsewhere.

In the still-dark Motor City, meanwhile, Detroit Police Chief Jerry Oliver  (search) said 22 people had been involved in some minor looting overnight.

The massive outage that started Thursday afternoon spread across the northeast quarter of the country, shutting off the lights and making air conditioners useless for million of people, including more than 2 million Michigan customers from Lansing to Detroit.

DTE Energy  (search) had restored power to 130,000 of them by Friday morning but warned that it could be the end of the weekend before all had electricity again.

In downtown Cleveland, half-illuminated high-rises and a lit-up Jacobs Field (search), home to the Indians, returned a look of normalcy to the skyline early Friday. But street and traffic lights were still dark, lending a sleepy atmosphere to the usually bustling rush hour.

All four of Cleveland's main water pumping stations failed during the blackout.

"I have no water and no lights so I might as well come to work," said attorney Lori Zocolo, who arrived at her downtown office at 5:30 a.m. wearing a T-shirt and shorts. She carried a business suit under one arm and said she hadn't been able to brush her teeth.

Power was restored early Friday to the four pumps that move water uphill from Lake Erie to 1.5 million customers in the city and suburbs, but water was just a trickle at faucets. Ohio Gov. Bob Taft  (search )authorized use of about two dozen National Guard tankers to begin distributing emergency drinking water.

Detroit Mayor Kwame Kilpatrick  (search) said the Detroit Water & Sewerage department, which serves much of southeast Michigan, was pumping about half of the water it usually handles as officials worked to get all its pumps back up and running following the power outage.

Low water pressure in some areas led officials to advise residents to boil water before drinking or cooking with it.

Michigan motorists making a pre-dawn morning commute to Detroit found a city largely in the dark, while across the Detroit River, Windsor, Ontario, was awash in light.

Vehicles attempting to cross the Canadian border jammed the Ambassador Bridge  (search)after being directed away from the Detroit-Windsor Tunnel, which was immediately closed when power failed Thursday but was reopened Friday.

In blacked-out cities, motorists were frustrated by their inability to buy gasoline at stations with electrical pumps.

The few Detroit stations that managed to secure backup power remained busy as was a powerless Target store where employees escorted customers one-by-one who needed to buy supplies such as batteries and water.

A Meijer station in Brighton ran out of gas about 7 a.m., leaving Brian Howse, 41, to sit on the tailgate of his truck with a cup of coffee and wait for the tanker expected to replenish the supply. Other gas stations in town had long lines that he couldn't wait in, he said.

"I'm afraid I might run out of gas if I'm waiting," Howse said. "Everywhere you go, the traffic's all backed up on the road. ... I don't want to wait all day. (But) if I have no choice, I have no choice."