Ten years ago, on September 11, 2001, New York City Fire Department Battalion Chief Joseph Pfeifer was on a routine call near the World Trade Center when disaster struck. Seeing the first aircraft hit the North Tower, he rushed to the scene and radioed the alarm, the first FDNY fire chief to take command. Today, Pfeifer is the New York City Fire Department’s Chief of Counterterrorism and Emergency Preparedness and a Citywide Command Chief. In examining leaders’ insights for a new expanded edition of The Leader’s Checklist, which is due out on September 20, Wharton management professor Michael Useem talked with Pfeifer recently about his leadership during the 9/11 rescue efforts, how that day has affected his command style, and what the New York City Fire Department and other cities are doing to prepare for the unexpected.

The following is an edited version of the conversation.

Michael Useem: Joe, it is great to have you here. I am going to begin by asking you about your career with the New York City Fire Department, which you joined in 1981. What have been some of the most formative experiences that helped you learn how to lead people?

Joseph Pfeifer: When I first came into the fire department as a probationary firefighter, I was told the most important thing is to know the job, to know what you need to do. So, I started reading the fire manuals and procedures. But that is only half of it. The other part is actually experiencing firefighting, which provides a tacit knowledge of how to force a door or how to climb an aerial ladder 100 feet in the air. But to be a good firefighter, to be good at anything, is really having the competency in knowing what to do.

As I became an officer, it was more than just knowing what to do, it became being responsible for firefighters. That point was made after 9/11, actually. I was in command of a three-alarm fire up in the Bronx. We had about 100 firefighters at the scene and about three dozen pieces of apparatus. When the fire goes out, I’m leaving and I have this firefighter running down the block after me. He calls, “Chief, chief, chief!” I stop and I turn around, and he says, “Chief, I just want to let you know that I’ll follow you down any hallway.” Now, for a firefighter, the most dangerous part is a hallway: It becomes like a chimney, and all the smoke and heat fills into the hallway. I thought, Wow, this is a very nice compliment.

Then, when I got back to my car, I realized he was saying more than “I’ll follow you.” He was saying, “I’ll be with you, I’ll follow you, and I want you to keep us safe.” See, leadership is not about giving orders; it’s about sharing the danger. That firefighter was saying that because of what I have done in the past, he’ll follow me, he’ll be with me during the next major event. That is an awesome responsibility. I could actually feel the pressure of the responsibility for others. And he meant what he said.

Useem: A formative moment.

Pfeifer: Very much so.

Useem: Joe, let me ask about a set of documents that I know you helped prepare, a set of checklists for the New York Fire Department. You have a checklist if there’s a radioactivity release. You have a checklist in case of a building collapse. You have a checklist called the Mayday checklist. Talk if you would about why you developed these checklists and then about how they are used in practice by members of the New York Fire Department.

Pfeifer: We use checklists as shortcuts. For a radiological incident, we don’t handle that frequently, so we need a list of procedures to follow. During a fire, as the fire becomes more and more complex and we have to make decisions, the stress level increases. One of the most difficult times as a commanding chief would be a Mayday. Mayday is a message from a firefighter that the firefighter is in trouble: The firefighter is trapped or doesn’t know his or her way out of the building. Something is seriously wrong, a life-or-death situation. Immediately the stress level goes up, and you have to deal with that, and at the same time, fight the fire. So, we use a checklist and an acronym. The word we use is LUNAR. What we want to know is the member’s location, his or her unit, the person’s name, the assignment and what resources we have available. That is critical information, so we can make sure that firefighter gets out of the building alive. It helps to know what to do right away, and it is very focused.

Another thing we are dealing with now is how to use technology as a checklist. For example, we are developing an electronic command board, or what I like to call a command pad, which is very similar to the iPad. We are able to see where our units are deployed within a building structure. One of the important things for safety is to do searches of every floor where there is fire, and even floors where there is no fire. We are required to do that within 15 minutes. As a checklist, we use visual cues. If the search is not completed within 15 minutes, the floor will turn red on the command pad. Instantly, that’s a cue to the incident commander to check on the statuses with searchers.

If we do a primary search it turns yellow. If we do secondary search afterward, it turns green. We use the intuitive knowledge of a stoplight — red, yellow, green — to give the incident commander the same cues as a checklist, but now we are doing it in a visual format.

Useem: Looking at the Mayday checklist, it looked to me as if you have a good number of items, all of which are pretty mission critical, and you probably want your officers to get through all of the items. One in particular caught my attention, having gone through your training program with seven of my colleagues a few months ago. The Mayday command is part of the checklist protocol. If you’re a trapped firefighter and you say, “Mayday,” you have to repeat it three times. Why is that important?

Pfeifer: It is important because we are dealing with wireless communications. We are dealing with radios. We want to make sure that the message comes across. If a firefighter is in trouble, the firefighter will say, “Mayday, Mayday, Mayday,” and then give a message. It helps ensure the message gets through. It also tells the other firefighters to stop talking on the radio and listen. In just three words, a lot is being communicated.

Useem: Speaking of Mayday, as fate would have it, on the morning of 9/11, you were down near the World Trade Center checking on a gas leak. It was a pretty routine day. You did look up a few minutes before 9:00 AM — at 8:46 to be very precise — and you saw the first plane hit the North Tower. You were the ranking commander in proximity to the World Trade Center. You played a very important role in bringing firefighters and emergency service people in there. You were also the incident commander in the North Tower. Just take us from 8:30 on the morning of 9/11, through the next couple of hours.

Pfeifer: On the morning of 9/11, we were checking a gas leak in the street, and it was pretty much a routine emergency for us. Then at 8:46 in the morning, we heard the loud roar of a plane. You never hear a plane going overhead in Manhattan because of the height of the buildings. We saw the plane actually aim and crash into the North Tower. At that moment, we knew we were going to the biggest fire of our lives. I got on the radio, and I gave the message to transmit a second alarm. I told the firefighters I was with to respond in with me.

About a minute later, I had just a little bit of time to think. I gave another message, and very clearly, I transmitted a third alarm for more resources. Then I said to the dispatcher that the plane had aimed for the building. I knew that this was not an accident, that this was a terrorist event. Then I proceeded to give further orders on where I wanted firefighters to stage and where I wanted them to go in.

I can remember stepping into the lobby of the World Trade Center’s North Tower. It looked like the plane had actually hit the lobby. There was debris all over the place, glass broken, people injured, some people burnt. I went up to the fire safety director, and I was told that the fire was somewhere above the 78th floor. As firefighters came in, I gave an order. The order was to go up, to evacuate people from the building and to rescue those who couldn’t get out by themselves. I told them to go up to the 70th floor. At the time, I figured eight floors was a good measure of safety. We would regroup there, and then try to get people out who were above the fire.

As we were doing that, a little bit before 9:00, we gave the order to evacuate the South Tower. But a few minutes later, at 9:03, we heard another loud roar, and this was the second plane crashing into the South Tower. At that point, we divided our command. There was one commander in the North Tower, one in the South Tower and our chief of department, the overall person in charge, was across the street. Firefighters came in, and they started to climb. They started to encourage people to come down: “Don’t stop. Keep going down. Keep moving down. Get out of the building.”

Then, at 9:59 that morning, we heard the crashing sound. We moved about 20 meters from where we were standing in the lobby to a passageway that led across West Street. The lobby was covered with dust, and it went completely black. Now, for firefighters, being in darkness is not a big deal. We operate in that all the time. But at that moment some of the other chiefs were saying we had to get out of the building, something very important to do. We had to move out. We couldn’t command in the lobby, we had to leave. I knew how to get out of the building. See, this was my building. I was there hundreds of times. That bought me some time to think. In that few seconds, I knew that if we couldn’t command there, we needed to get the firefighters out also. So I picked up my handy radio, and I said, “Command to all units in Tower 1, evacuate the building.” And the firefighters started to come down.

But being many floors above, it took a long time to come down. What we didn’t realize at the time was that we were running out of time. As firefighters came down, they didn’t think of just themselves. One lieutenant I can remember stopped around the ninth floor and directed other firefighters to other stairs because the stairs they were coming down would have led to the debris-filled courtyard. Another unit, Ladder Six, stopped and noticed a woman who couldn’t continue any longer. They picked her up and started to carry her down.

We made our way out into the street, and standing in front of the World Trade Center, we couldn’t tell what had happened. It was covered with dust and debris, and we were never told that an entire 110-story building had just collapsed to the ground. Then, at 10:28 that morning, we heard the crashing and the roar of the North Tower collapsing, and we began to run. But with bunker gear, you can’t run that fast or that far. So we crouched down behind a truck, and this beautiful summer morning that was full of sunshine turned completely black. You couldn’t see your hand in front of your face. We could hear the steel crashing all around us, and we were just waiting, really, to be crushed because we knew we were too close to the World Trade Center.

Then the noises stopped, and it became silent. There was no more talk on the radio. There was just this eerie sound of total silence. It was like a new snowfall. You just heard nothing. It was just this muffled sound. When we got up and we walked back to the Trade Center, or where the Trade Center had been, we saw only rubble. We couldn’t believe that the buildings — the two towers — had just crashed to the ground. On my radio, I heard a call from Ladder Six, “Ladder Six to command, we’re trapped in the B stairs on the fourth floor.” Well, I looked at the pile, and although I knew the building well, I had no idea where the captain was.

That was the captain who was carrying the woman down. By slowing their descent, they were able to survive in a little pocket. That captain got his unit and the woman out alive, a miraculous story. But there were other stories: that lieutenant for Engine 33 and the 343 firefighters who died. In total, we lost 2,750 people in New York. But amongst the rubble and amongst the pain, we saw glimmers of hope. See, terrorism tries to take away people’s hope. But what we saw that day is people helping each other. What we saw in the days and months to follow was the silhouette of a firefighter on the pile at Ground Zero searching to make rescues initially and then to recover those who were lost.

It is important that we don’t focus just on the sadness of that day because we did save 20,000 people. And 9/11 is something different: It’s not just an event for New York City, or just an event for the United States; it’s an international event because no matter where you were in the world, you experienced it through the media, a type of global trauma. But 10 years after 9/11, it gives the international community a voice against terrorism — that small roadside bombing, that hotel bombing. It’s a united voice, a world voice that says terrorism is wrong. As we look at the tenth 9/11 anniversary, and other anniversaries, it is really an international event that gives all victims of terrorism a voice.

Useem: Joe, I know in the 10 years since 9/11, you have spent a lot of time thinking about that event, including its implications for leadership and for getting through a crisis of that kind. You work with the 9/11 Commission. You have written about what happened and some of the lessons learned. Please talk about a couple of the leading lessons that you have now worked with since the events of that terrible day.

Pfeifer: I think the 9/11 Commission Report captured it well by saying that there was a lack of information-sharing. Certainly there was a lack of information-sharing with the intelligence community before the events of 9/11. But there was also a lack of information-sharing among emergency responders, the police and fire department. I think one of the important lessons learned is that during a catastrophic event, during a disaster, we need to share information. There is also a sense of interdependency. We need to work together.

One of the things that I wrote about is that during any major event, there will always be organizational bias. As the stress of an incident increases, groups turn to their own: firefighters go to firefighters, police go to police and emergency medical form their own groups. But during a disaster, we need just the opposite. We need for those groups to collaborate. As we look at other major disasters around the world — an earthquake, a tsunami, another terrorist event — it is necessary for groups to come together and communicate and work with each other to deal with the disaster at hand.

Useem: I know you have spent a lot of time building that integration and ability to communicate since then. As you have taken on additional duties now as Chief of Counterterrorism for the City of New York, what keeps you up at night these days, 10 years after 9/11?

Pfeifer: With my job, there is a lot of things that keep me up at night. One of the things that I worry about the most is the type of attack that we saw occur a few years ago in Mumbai. As a matter of fact, it is referred to as a Mumbai-style attack, where there are multiple active shooters in different locations using improvised explosive devices and fire. It’s those three weapons — guns, explosives and fire — that keep me up at night. In combination, they are the most deadly. The World Trade Center was brought down not by the planes, but by fire. We see that terrorists are starting to learn from their own activity. And we also must learn.

For us to battle an event that uses multiple means of weapons, multiple means of attack, we need to work with each other. It’s something that worries us in New York. I’m in contact with London, and it worries them. But I think by sharing information within the city of New York and with other cities, we will be better prepared to deal with that type of event, if it does occur.

Useem: Joe, a final question for you. You have been with the New York City Fire Department for 30 years. You were at Ground Zero on 9/11. For the last decade you have thought a lot about how to build out of that to prepare for whatever may happen in the future. These types of catastrophic events have been brought home as we watch what happened with BP in the Gulf, the Fukushima power plants in Japan, the disaster in Haiti with that earthquake. On the basis of your experience with the New York Fire Department, 9/11 and the decade since then, what advice would you have for people who are responsible in the private sector, public sector and in nonprofit organizations for thinking about how to get through a catastrophic event?

Pfeifer: When we look at those events, we want to think of how to manage it, or as the military refers to it, command and control. We want one person to run the whole thing. And I think what we have learned since 9/11 and looking at those major events, that is not what leaders do. Leaders during a catastrophic event do more than just manage the event. They do three other things: they connect, collaborate and coordinate.

When an event occurs, the first thing that needs to be done is to hastily form networks at the scene of the incident, among firefighters, rescuers, law enforcement and medical personnel, so they can start to communicate and work together. Away from the incident, we have to connect to those emergency operations centers that we have created and have information passed from, for example, New York City to the state, to the national operations center down in Washington, D.C.

Once we have formed these networks, the incident commanders, the people who are responsible for dealing with the event, need to get together and collaborate. So there’s this flattening of command, not just one person. Now we have the major decision-makers getting together and figuring out what to do. What they do is coordinate the resources that we need to get a job done. What we are seeing now is that it’s not just one resource; it involves multiple resources. For example, during Hurricane Katrina in New Orleans, we had the coastguard spot fires. The New Orleans Fire Department, with the assistance of the New York City Fire Department, went out and extinguished the fires. But they also went out with law enforcement for protection. It was that combination and coordination of resources. When we look at leadership during a disaster, whether it is in an emergency response or in business or in nonprofits, it is the combination of what we call C5: command and control, connect, collaborate and coordinate.

Useem: Joe, on that note, let me thank you for 30 years of service to the City of New York. Let me thank you for putting your leadership and your life on the line on that very fateful morning on 9/11. And thank you for your insights that have come with a decade of reflecting on 9/11 and all the threats that we now face, so that the rest of us can be more prepared to face those calamities that may be out there one day. We need to be ready to do what we have to do if, heaven forbid, we do face another disaster.

Pfeifer: Thank you, Mike.