WASHINGTON (USA TODAY) -- Hospital trauma centers in seven major cities do not have the capacity to handle even a modest terrorist attack, according to findings released Monday from a House committee investigation.

Lawmakers looked into hospitals' ability to deal with a sudden influx of victims in the five cities considered at highest risk for terrorist attack and in the two cities hosting this summer's political conventions.

The 34 hospitals surveyed in New York City, Washington, Los Angeles, Chicago, Houston, Denver and Minneapolis had no space in their emergency rooms to treat a sudden surge of victims, few available beds in their intensive care units and too few regular beds to handle even those with less serious injuries.

Hospitals in Washington and Los Angeles were particularly overburdened, said Henry Waxman, D-Calif., chairman of the House Committee on Oversight and Government Reform. He called the inquiry's results "truly alarming."

The survey was taken March 25 at 4:30 p.m. local time in each city. The date was chosen at random; the time was chosen because it was neither the busiest nor slowest time of day in emergency rooms.

"If a terrorist attack had occurred on March 25 when we did our survey, the consequences would have been catastrophic," Waxman said. "The emergency care systems were stretched to the breaking point and had no capacity to respond to a surge of victims."

Rep. Christopher Shays, R-Conn., said there's no easy way to prepare for mass casualties. "We cannot afford to build and maintain idle trauma facilities, waiting for the tragic day we pray never comes," he said.

Some cities have contingency plans for crises that involve reopening closed hospitals and using large public spaces to set up makeshift hospitals.

Irwin Redlener, director of the National Center for Disaster Preparedness at Columbia University in New York, said those efforts would help -- but not much because most emergency rooms are already over capacity. "For a really serious catastrophic acute event -- a nuclear detonation or widespread chemical attack where you have thousands of victims simultaneously -- there is no urban area that is prepared for large-scale disasters," he says.

Waxman and emergency care experts said new government regulations reducing federal Medicaid reimbursements to hospitals will further strain the nation's overcrowded emergency rooms.

A decrease in federal funds "will severely cripple our ability to meet the nation's needs for emergency care, whether delivered under everyday conditions or in the extraordinary setting of a mass casualty event," said Roger Lewis, an emergency room doctor at the Harbor-UCLA Medical Center in Los Angeles County.

On Wednesday, Health and Human Services Secretary Mike Leavitt and Homeland Security Secretary Michael Chertoff will testify on the implications for national preparedness.

Copyright 2008 USA TODAY, a division of Gannett Co. Inc.