WASHINGTON - Federal and local health officials are preparing for the possibility of a new SARS outbreak, yet hospitals may still be overwhelmed because they lack key workers and equipment, congressional investigators report.

The outbreak of severe acute respiratory syndrome in the United States this year was successfully contained. Worldwide, SARS sickened more than 8,400 people and killed at least 812. Nearby, in Toronto, there were nearly 250 cases and 39 deaths. The United States reported just 73 cases and no deaths.

But the toll could be higher if the SARS virus re-emerges, experts warn. The World Health Organization said earlier this month that SARS had been contained globally, but experts believe it may return with colder weather, like the flu does each year.

In a report being released Wednesday, the General Accounting Office warned that in a large-scale outbreak, entire hospital wards and their staffs may be needed as SARS isolation facilities. Or entire hospitals might need to be designated as SARS hospitals.

It could lead to "severe overcrowding" at hospitals, particularly if SARS hits during the peak flu season, said the GAO, which is the investigative arm of Congress.

"Most hospitals lack the capacity to respond to large-scale infectious disease outbreaks," the GAO said in a report being released at a Senate Government Affairs subcommittee hearing.

Specifically, the GAO said, few hospitals have adequate staff or equipment - such as N-95 respirators - needed to care for a large number of potentially infectious patients.

Hospitals report that they need more equipment as well as capital improvements such as quarantine and isolation facilities and air handling and filtering equipment. A GAO survey of more than 2,000 hospitals found that few had the equipment and supplies needed to handle a large-scale infectious disease outbreak.

It's a problem that the nation must prepare for, said Sen. Norm Coleman, chairman of the Senate Government Affairs investigations subcommittee.

"We need regional and national plans for dealing with a large-scale outbreak of SARS," Coleman, R-Minn., said in a statement. "We saw in Toronto that SARS can quickly overwhelm even a modern health care system if the first cases are not quickly contained. When this happens, regional and national resources must be available to fill in the gap."

Dr. James Hughes of the federal Centers for Disease Control and Prevention said CDC officials were doing a variety of things to prepare for another SARS outbreak. That includes developing guidance for hospitals as to what infection control measures are necessary given a variety of threat levels. CDC is also working with others to develop better diagnostic tests and to enhance quarantine facilities at airports.

"We do not know if SARS will reappear, but we must assume it will," Hughes said.