Nearly a quarter-million homes and businesses still had no electricity Monday as the city struggled to recover from last week's devastating thunderstorms.

The blackout has kept air conditioners from cooling homes since Wednesday, while temperatures outside soared into triple digits.

As of Monday morning, about 231,000 customers were still without power, according to Ameren Corp. That was down from the more than a half-million customers that lost power when the storms struck.

With about 4,000 utility workers from as far away as Arizona working around the clock to restore service, Ameren Vice President Richard Mark said 90 percent could have power again by Tuesday, with the rest expected to have electricity Wednesday.

The blackout has left emergency rooms across the region inundated with patients who rely on electricity for oxygen and other medical needs.

The Missouri Health Department called on the help of all registered nurses and nursing assistants in the area and a team of nurses arrived Saturday from Kansas City to work in St. Louis hospitals. National Guard troops went door-to-door to check on the elderly. At least four deaths in the region were blamed on the storms or the heat.

Blackouts also affected parts of California on Monday, where utilities worked to restore electricity to thousands of customers Monday as a severe heat wave taxed power plants and threatened to push the state into a power emergency with the potential for more blackouts.

In New York City, 3,000 to 4,000 customers, including homes, businesses and in some cases entire apartment buildings, entered their second week without electricity Monday in part of the borough of Queens. That blackout started in the middle of last week's heat wave on a day the temperature was near 100 degrees.

In St. Louis, some 100 dump trucks rolled through city streets Sunday collecting branches and entire trees smashed by the storms. The Missouri Army National Guard was helping with the cleanup.

"It's hard to believe your eyes when you are looking at something this massive," said St. Louis Parks Director Gary Bess. What isn't turned chopped into mulch for landscaping will be cut into free firewood or hauled away, he said.

President Bush on Friday approved Missouri's request for an expedited disaster declaration, which mobilizes the Federal Emergency Management Agency and provides federal funding for debris removal and other emergency needs.