WASHINGTON — For one day at least, Mayor Giuliani and his September 11 legacy were spared.

Facing the anger and scorn of Democratic lawmakers and a hearing room full of former ground zero rescue workers, Christine Todd Whitman yesterday had her best chance to take a swipe at the former mayor and current presidential contender, and to blame him and his administration for failing to enforce safety precautions at the World Trade Center in the aftermath of the terrorist attacks nearly six years ago. Instead, Ms. Whitman, the former chief of the Environmental Protection Agency, came to the city’s — and Mr. Giuliani’s — defense.

“I think the city of New York did absolutely everything in its power to do what was right by the citizens of New York,” Ms. Whitman told a House subcommittee yesterday, when asked directly by Rep. Bill Pascrell of New Jersey if the city “acted responsibly” following the attacks.

In offering the city such a sweeping compliment, Ms. Whitman ratcheted down a long-fought battle with Mr. Giuliani and gave a reprieve to his presidential campaign, which has relied heavily on the former mayor’s reputation for calm and decisive leadership in the chaotic months after September 11, 2001.

Before yesterday, she had repeatedly faulted the city for not forcing rescue and recovery workers at ground zero to wear respirators to protect them from the toxic dust in the air. Mr. Giuliani and his aides have countered that Ms. Whitman and the EPA told them the air was safe to breathe.

As recently as Friday, the Giuliani campaign responded to an interview she gave to WNBC by releasing a statement from a former deputy mayor, Joseph Lhota, saying Ms. Whitman “never voiced any of these concerns at the time” and calling her claims “revisionist at best.”

Ms. Whitman, a Republican who served as governor of New Jersey before President Bush picked her to head the EPA in 2001, sought the high road at yesterday’s hearing.

“Let’s be clear: There are indeed people to blame,” she said at the outset. “They are the terrorists who attacked the United States, not the men and women at all levels of government who worked heroically to protect this country.”

She repeatedly declined to criticize the Giuliani administration and dismissed the suggestion of a rift between them as a creation of the press.

“I don’t think that the mayor was blaming me. I certainly was not blaming the mayor,” she said.

From Mr. Giuliani’s camp, there was quiet yesterday; his campaign offered no comment on Ms. Whitman’s testimony.

For three hours, Ms. Whitman defended herself and the EPA under heated questioning from federal legislators, led by Rep. Jerrold Nadler, who represents Lower Manhattan and chaired the hearing. She has come under intense criticism for her actions after September 11, chiefly her now-infamous statement six days after the attacks offering reassurance to the public that the air near ground zero was “safe to breathe.”

Mr. Nadler and other lawmakers have accused her of deliberately misleading the public in an effort to quickly reopen Lower Manhattan, and Wall Street in particular. Those criticisms have increased as studies have begun to show a link between the poisonous dust near the World Trade Center site and respiratory illnesses.

Ms. Whitman said that suggestion was “utterly false,” calling it a “destructive and incendiary” charge.

Pressed directly by Mr. Nadler to acknowledge a mistake, she refused. “Sir, I do not regret that statement,” she told him, saying it was supported by scientists and air testing data at the time. She insisted that the EPA was transparent in posting its data publicly and reiterated its repeated instructions for ground zero workers to wear protective equipment when they toiled at the site.

Later in the hearing, she defended the Bush administration’s desire to get the area back up and running as soon as possible.

“Safety was first and foremost, but we were not going to let the terrorists win,” Ms. Whitman said, drawing jeers from the dozens of activists and former rescue workers in attendance.

She appeared calm through most of the hearing, her answers firm though largely polite, but her frustration peaked during an exchange with Rep. Keith Ellison, a Democrat of Minnesota. “These were not whims, these were not decisions by a politician. Everything I said was based on what I was hearing from professionals.” Ms. Whitman said. “My son was in Building 7, Congressman, and I almost lost him.”

Mr. Ellison interjected: “I’m not going to let you turn this into a personal thing.”

Throughout her appearance yesterday, Ms. Whitman expressed her disappointment at the tone of the public debate over the EPA’s actions. The agency’s employees, she said at one point, “were heroes as much as everyone.”

“It was unprecedented,” she said of the September 11 aftermath. “We were doing the very best we could.”

Among the rescue workers in attendance, few appeared satisfied with Ms. Whitman’s testimony.

“She sidestepped every question. She danced around,” a retired police officer who worked for three months at ground zero, David Maloney, said.