Democrats called the 389-30 vote an indictment in connection with a shooting incident there that left 11 Iraqis dead. Senate Democratic leaders said they planned to follow suit with similar legislation and send a bill to President Bush as soon as possible.
"There is simply no excuse for the de facto legal immunity for tens of thousands of individuals working in countries" on behalf of the United States, said Rep. Sheila Jackson-Lee, D-Texas.
The FBI is currently leading an investigation into the Sept. 16 shootout, although administration officials acknowledge they are unsure whether U.S. courts would have jurisdiction in the case or others like it.
In a separate incident, a drunk Blackwater employee left a Christmas Eve party in Baghdad and fatally shot the guard of one of Iraq's vice presidents. That contractor was fired, fined and returned home to the United States, but no charges have been filed.
"We are a new phenomenon in land warfare," private defense contractor Carter Andress told CBS News correspondent Elizabeth Palmer. "The legal structure on how to hold us accountable has not been fully developed."
The current law, called the Military Extraterritorial Jurisdiction Act, covers personnel supporting the mission of Defense Department operations overseas. But because Blackwater's primary mission is to protect State Department officials, defense lawyers would likely argue that the law doesn't apply.
At the same time, all U.S. contractors are immune from prosecution by Iraqi courts.
"I think that there should be accountability under the Military Extraterritorial Jurisdiction Act," Andress told Palmer.
The bill's passage came on the same day that a government minister told The Associated Press that the official Iraqi investigation said Blackwater security guards involved in the September incident face trial in Iraqi courts and the company should pay compensation to the victims.
The White House and congressional Republicans said they support the intent of the bill, but thought it was drafted poorly and could have unintended consequences.
In a statement issued Wednesday, the White House said the bill would have "unintended and intolerable consequences for crucial and necessary national security activities and operations." The statement did not explain further or give examples on how the bill would affect national security.
The White House referred questions to the Justice Department, which declined to comment.
Prior to passage, the House voted 342-75 to ensure the legislation would not affect intelligence operations.
Rep. Chris Shays, R-Conn., accused Democrats of rushing the bill through Congress in a partisan bid to criticize the Bush administration's handling of the war.
"It is amazing to me the number of men in Blackwater that have lost their lives and we never hear it on the other side of the aisle," Shays said. "Blackwater is evil. That's the way it appears in all the dialogue."
Rep. David Price, who sponsored the bill, said the White House's objections were unfounded and "should infuriate anyone who believes in the rule of law."
Blackwater founder Erik Prince told a House panel Tuesday that he supports expanding the law.
"Beyond firing him for breaking the rules, withholding any funds we can, we can't flog him," Prince said of the intoxicated Blackwater guard. "We can't incarcerate him. We can't do anything beyond that."
FBI agents will take control of the Sept. 16 probe from the State Department's Bureau of Diplomatic Security as soon as a full team has been assembled in the Iraqi capital, State Department spokesman Sean McCormack told reporters on Thursday.
Even the FBI relies on Blackwater to protect its agents in Iraq, reports CBS National Security correspondent David Martin. But this time, when FBI agents visit the scene of the Blackwater shooting, they will be guarded by U.S. government security agents.
McCormack stressed that the step did not necessarily imply that the investigation would result in criminal charges being brought against the contractors.