Sept. 7 (Bloomberg) -- New Orleans rescue workers intensified efforts to find survivors of Hurricane Katrina while Mayor Ray Nagin authorized police to forcibly remove residents who remain nine days after the storm and the flood that followed.

President George W. Bush and Congress announced separate investigations of the response to the disaster, and the government made plans to spend more on recovery operations. Bush will request $51.8 billion more, bringing total Katrina aid to $62.3 billion, White House Spokesman Scott McClellan said.

More than a week after the storm tore into the northern coast of the Gulf of Mexico with winds of 140 mph (225 kph), as many as 15,000 people remain in the city, said Lieutenant Colonel Jacques Thibodeaux of the Louisiana National Guard. Officials have called the storm, which probably killed thousands, the worst natural disaster in U.S. history.

``Police are now able to force people that want to stay in the city to leave because of the danger they face,'' Sergeant Nicholas Stahl, of the Louisiana Office of Homeland Security and Emergency Preparedness, said today in a telephone interview.

The Congressional Budget Office estimated that the Aug. 29 storm, which devastated parts of Louisiana, Mississippi and Alabama, will cut 400,000 jobs from U.S. payrolls this year and will slow U.S. economic growth by 0.5 to 1 percentage point.

Cost Rising

Senate Majority Leader Bill Frist, Republican from Tennessee, said today that initial recovery and relief operations may cost $100 billion to $200 billion.

Homeland Security Secretary Michael Chertoff told lawmakers last night that as many as 10,000 people may have died, Maryland Democrat Representative Elijah Cummings said. The hurricane may have been the deadliest U.S. storm since one that swept through Galveston, Texas, in 1900, killing 8,000 to 12,000. The 1906 San Francisco earthquake and fire killed 5,000 to 6,000.

The official death count has reached almost 300. Louisiana has recorded 83 dead, said Bob Johannessen, a spokesman for the state's Health and Hospitals Department. Last night, Mississippi Governor Haley Barbour put the state's death toll at 196.

Katrina killed 11 people earlier, when it crossed Florida before entering the Gulf. Two others were killed in Alabama in traffic accidents during the storm, said Alabama Emergency Management Agency spokesman Scott Adcock.

Threat Rising, Too

New Orleans Mayor Nagin changed his evacuation order late yesterday to ``mandatory'' from ``strongly recommended'' because of the danger to residents. Fires light the New Orleans skyline, and the risk of disease from the polluted floodwaters threatens to increase the death toll, health officials have said.

Four people have died of a water-borne illnesses, the U.S. Centers for Disease Control and Prevention said, citing reports from local health officials.

New Orleans's contaminated floodwater contains levels of E. coli and lead that are at least 10 times more than what's considered safe, the U.S. Environmental Protection Agency said today.

Forced evacuations will take place within days, and the military won't be involved, Cable News Network reported. The National Guard and Louisiana's Homeland Security department aren't forcing people from their homes, Art Jones, a disaster-relief coordinator at the department said. He said his agency hasn't received any order from Nagin's office to evict residents.

Military Presence

A total of 63,000 troops are aiding the relief effort -- 18,000 active-duty troops and 45,000 National Guard, Lieutenant General Joseph Inge, deputy commander of the U.S. Northern Command, told a Pentagon press briefing today.

Forces from two other nations also are assisting, Inge said. Canadian divers are helping with harbor reconstruction off Pascagoula, Mississippi, and Mexico sent a ship that will help in search-and-rescue efforts. The U.S. has accepted about $1 billion in cash and other aid from foreign donors, including $400 million in crude oil from Kuwait, said Harry Thomas, the State Department's executive secretary.

The Katrina relief effort has collected more than $504 million, the Chronicle of Philanthropy said. Most has gone to the American Red Cross.

The U.S. House of Representatives is scheduled to consider the additional spending measure tomorrow. Of the funds in the latest request, $50 billion will go to the Federal Emergency Management Agency. The Defense Department will receive $1.4 billion, and $400 million will go to the U.S. Army Corps of Engineers, McClellan said.

Reviewing Response

Bush, battered by criticism that his administration failed to respond fast enough, said yesterday he will call for an investigation of the federal government's response. A CNN/USA Today/Gallup poll found that 42 percent of Americans say the federal response to Katrina was ``bad'' or ``terrible.''

The reaction of federal agencies was rated ``good'' or ``great'' by 35 percent of respondents in the poll of 609 adults conducted Sept. 5 and 6. The poll's margin of error is 4 percent points.

The Senate will begin public hearings as early as next week into the ``failures of all levels of government,'' said Susan Collins, a Maine Republican and chairwoman of the Homeland Security and Government Affairs Committee.

The Associated Press, citing internal documents, said the head of FEMA waited for hours after the hurricane hit before asking his boss to send 1,000 employees to help with the rescue.

Looking Good

FEMA director Michael Brown sent an Aug. 29 memo to Chertoff, his boss, about five hours after the storm struck. It said employees would arrive in the Gulf coast areas within two days as part of an effort to ``convey a positive image'' of the government's effort to help, the AP reported, citing the memo.

``These were administrative, clerical and support functions,'' not emergency workers, Homeland Security Department spokesman Russ Knocke said in an interview. They would have had to undergo at least a day of disaster training before being deployed.

Hillary Clinton repeated her call for the separation of FEMA from the Homeland Security Department, which is focused mainly on combating terrorism, and elevating its chief to the president's cabinet.

``When FEMA was moved into the Department of Homeland Security, its traditional mission of trying to prepare for, and recover from, and respond to, disasters was subsumed in what became the overall mission in the war against terrorism,'' Clinton, a Democratic Senator from New York, said on CNN.

Walking-Around Money

FEMA said today it will distribute $2,000 debit cards to Katrina survivors to buy emergency supplies.

Stahl, of Louisiana's emergency preparedness office, said authorities estimated it will take at least five weeks to drain New Orleans and as long as 12 more weeks before the city is dry enough to allow demolitions and rebuilding.

Engineers are working ``around the clock'' to repair two breaches in the London Avenue Canal, as well as breaks in the Industrial Canal, Steven Keen, a project manager with the Army Corps of Engineers, said today in a telephone interview from New Orleans. The smaller breach is almost plugged with sandbags, officials said today.

There were 23 of 148 pumps working in New Orleans today, said Dan Hitchings, a engineer corps spokesman. Many pumps are still submerged and need to be dried out. Officials are concerned corpses will be pumped into Lake Pontchartrain, spokesman John Rickey told reporters today.

Signs of Progress

``The water level is definitely dropping, though the rate depends on the area,'' Keen said. Engineers are reinforcing the 17th Street Canal, whose breach was patched two days ago, to prevent further breaks, he said.

One casualty of the storm may be the Superdome, the 30-year- old, 70,000-seat arena that is home for the National Football League's New Orleans Saints and which also hosts political conventions, Super Bowls and college basketball tournaments.

Damage to the state-owned arena, which sheltered Katrina evacuees in New Orleans, probably exceeds $100 million, said Doug Thornton, regional vice president of SMG, the sports arena's management company.

Seventy percent of the dome's roof, 170 feet above street level has failed, he said. The athletic field is covered by about 2 inches of standing water and is ruined. Many of the mechanical systems, such as elevators, electrics and plumbing are destroyed, Thornton said.

Oil Production

Katrina gutted energy production in the Gulf of Mexico, source of about a third of the oil consumed in the U.S. and about a quarter of the natural gas.

Katrina shut down 860,568 barrels of daily oil output, or 57 percent of normal Gulf production, the U.S. Minerals Management Service said in a report today. Since Aug. 26, when the storm threatened the area, Katrina has thwarted the output of more than 13.6 million barrels of oil, or 2.5 percent of the Gulf area's annual capacity, the service said.

Other storms are brewing in the Atlantic Ocean. Warnings were issued along Florida's eastern coast for Ophelia, which strengthened to a tropical storm today.

At 5 p.m. New York time, Ophelia was 80 miles (128 kilometers) east-northeast of Cape Canaveral, Florida, and was almost stationary, according to the National Hurricane Center. Maximum sustained winds approached 50 mph, with faster gusts.

Hurricane Maria, with maximum sustained winds of about 80 mph, was 875 miles east-northeast of Bermuda, the center said. Maria is forecast to weaken and to remain at sea. Hurricane Nate, with winds of 85 mph, was about 200 miles south-southwest of Bermuda and was forecast to make its closest approach to the island tomorrow morning, the hurricane center said.