The city’s highest-ranking fire officer broke with the Bloomberg administration yesterday, telling a City Council committee the city’s new emergency response plan was “bad policy” that “does not make any sense.”

In an unprecedented move that pits him squarely against his bosses, Chief Peter Hayden said the plan jeopardizes the safety of rescue workers and the public because it undermines the Fire Department’s ability to rescue victims and participate in on-scene strategy.

“I think it’s bad policy, I think it’s a bad document,” Mr. Hayden told council members during a standing-room only hearing.

“If the objective and the role of that document was to clarify the roles and responsibilities of each agency, it’s failed,” Mr. Hayden said.

The dispute stems from an emergency plan that Mr. Bloomberg put into effect last month. The plan, which is known as the Citywide Incident Management System, puts the police in charge of emergency scenes where chemical, biological, radiological, or nuclear materials are suspected. Once police determine an incident is not a terrorist attack or a crime, control is turned over to the Fire Department.

After the September 11, 2001, attacks, the federal government ordered cities nationwide to adopt formal response plans. In New York, the primary goal is to ensure that the communications breakdown that plagued responders at the World Trade Center in 2001 does not happen again.

On that morning, police officers in helicopters saw that one of the buildings was on the brink of collapse, but the information was never communicated to firefighters who were still climbing stairwells inside the tower.

The city’s new plan, under review for the past two years, was propelled into the spotlight a few weeks ago when Mr. Hayden’s concerns first became public. Since then it has stirred up the long running feud between the departments over which is better equipped to handle those types of emergencies.

Yesterday, the police commissioner, Raymond Kelly; the fire commissioner, Nicholas Scoppetta, and the head of emergency management, Joseph Bruno, defended the Bloomberg administration’s choice.

Given the threat from Al Qaeda and its “franchise groups,” figuring out the nature of all incidents from the outset is crucial, Mr. Kelly said. Doing so, he said, allows the police to determine if a second incident is imminent and if people outside the area are in danger.

“You are talking about the possibility of hundreds of thousands of casualties, hundreds of thousands of lives in a successful attack,” Mr. Kelly said after testifying.

The sticking point for many council members was what they viewed as an inconsistency in the plan. Mr. Kelly repeatedly said that while the police would be in command of these scenes, officers would not interfere with firefighters; rescue operations. Saving lives, he said, was always the top priority.

That answer did not makes sense to some council members, rank-and-file firefighters, or Mr. Hayden, who has 36 years on the job. The plan’s opponents said putting the police in charge indicates that gathering evidence takes precedence over saving victims. They also said implementing a command structure that does not need to be followed would cause confusion.

“It’s very clear to me and I think to many people in this audience, they are very confused,” Mr. Hayden said of the commissioners who testified. “If they’re confused, I’m confused and the police officers in the street are going to be confused and there will be a compromise of safety.”

The speaker of the City Council, Gifford Miller – who is one of the Democrats running for Mr. Bloomberg’s job – and other opponents of the plan called on the mayor to revise it and to give police and fire officials joint control.

Mr. Hayden said fire officials should at least have equal footing at these scenes. If the city insists on choosing one lead agency, the Fire Department is better equipped, he said. In other parts of the country fire officials take the lead. Mr. Kelly said New York is unique.

Mr. Scoppetta, who advocated in the past for the Fire Department to take the lead role, had a more muted response than the other two commission ers but said he would abide by the plan. He acknowledged that, for any plan to work, the “rivalries” and “turf battles” must end.

Meanwhile, fire officials conducted a terrorism drill yesterday morning at the same time the hearing was going on. The timing of the drill raised eye brows in the Council, but the department insisted it was scheduled before they knew of the hearing.

The mayor’s press secretary, Edward Skyler, said giving police the authority to determine whether an incident is terrorist-related is “the responsible thing to do.”