The New York Police Department, the F.B.I. and the city's health department have agreed for the first time on a set of rules that will govern investigations of suspected biological attacks in the city, detailing the roles the agencies will play as well as how confidential medical information is to be shared.
The ''protocol,'' a six-page document that officials regard as something of a remarkable cooperation agreement, resulted in part from lessons learned in New York during the 2001 anthrax letter attacks, which killed five people in Florida and the Northeast and infected more than a dozen others in the months after the Sept. 11 strikes.
The anthrax investigations, and several subsequent inquiries into suspected germ attacks, were strained by tension between health and law enforcement officials over turf and procedures.
The accord, which was worked out in confidential, sometimes contentious meetings over the last two years, states that while law enforcement officials have the lead in investigating any terrorist crime, such investigations must be conducted jointly with the Department of Health and Mental Hygiene since physicians are likely to be the first to identify a victim of a germ attack.
To aid that effort, the protocol agreement details some novel compromises among agencies that sometimes have competing interests.
For instance, law enforcement officials, in the course of a bioterrorism investigation, will have access to the once typically confidential medical information of those who might have become infected. But the police and F.B.I. must keep such information confidential. And to encourage sick people to seek medical help, law enforcement agencies have agreed essentially to overlook a sick person's immigration problems or minor criminal activities.
The agreement also lays out some minor but still meaningful tactics. For example, law enforcement officials involved in interviews of patients will, by design, not wear uniforms, to avoid intimidating possible victims. And while patients will be interviewed jointly by teams of medical and law enforcement officials, physicians will be authorized to ask police and federal agents to leave the room.
''This is a groundbreaking agreement in uncharted waters,'' said Michael A. Sheehan, the Police Department's deputy commissioner for counterterrorism. ''Both law enforcement and the public health community have made some tough compromises on what they consider sacred ground. But New Yorkers will be safer and healthier for it.''
With the agreement, which was signed a month ago by Thomas R. Frieden, the health commissioner; Raymond W. Kelly, the police commissioner; and Pasquale J. D'Amuro, the assistant director of the F.B.I.'s New York office, New York becomes the first city in the nation to have adopted such a formalized protocol.
Richard A. Falkenrath, President Bush's former deputy homeland security adviser, said that he knew of no comparable agreement at the federal level and that New York was ahead of other cities in trying to systematically sort through the roles of public health and law enforcement officials in a potential bioterrorist attack. ''This is in the public interest to do,'' Mr. Falkenrath said.
A copy of the internal protocol was provided to The New York Times. It provides for joint training of law enforcement and public health officials that is scheduled to start in January.
The agreement has not solved all outstanding issues. For instance, it does not state when and how quickly public health officials must notify the F.B.I. and police if they come across someone who may be infected with a dangerous germ. Officials said that law enforcement and health officials were still discussing which germs should require immediate notification and joint investigations as part of a separate agreement, a so-called ''annex'' to the broader agreement.