I was about 10 years old on a camping trip with my dad in the Adirondack Mountains, a wilderness area in the northern part of New York State. It was a beautiful day. The forest was sparkling. The sun made the leaves glow like stained glass, and if it weren't for the path we were following, we could almost pretend we were the first human beings to ever walk that land. We got to our campsite. It was a lean-to on a bluff looking over a crystal, beautiful lake, when I discovered a horror. Behind the lean-to was a dump, maybe 40 feet square with rotting apple cores and balled-up aluminum foil, and a dead sneaker. And I was astonished, I was very angry, and I was deeply confused. The campers who were too lazy to take out what they had brought in, who did they think would clean up after them? That question stayed with me, and it simplified a little. Who cleans up after us? However you configure or wherever you place the us, who cleans up after us in Istanbul? Who cleans up after us in Rio or in Paris or in London? Here in New York, the Department of Sanitation cleans up after us, to the tune of 11,000 tons of garbage and 2,000 tons of recyclables every day. I wanted to get to know them as individuals. I wanted to understand who takes the job. What's it like to wear the uniform and bear that burden? So I started a research project with them. I rode in the trucks and walked the routes and interviewed people in offices and facilities all over the city, and I learned a lot, but I was still an outsider. I needed to go deeper. So I took the job as a sanitation worker. I didn't just ride in the trucks now. I drove the trucks. And I operated the mechanical brooms and I plowed the snow. It was a remarkable privilege and an amazing education. Everyone asks about the smell. It's there, but it's not as prevalent as you think, and on days when it is really bad, you get used to it rather quickly. The weight takes a long time to get used to. I knew people who were several years on the job whose bodies were still adjusting to the burden of bearing on your body tons of trash every week. Then there's the danger. According to the Bureau of Labor Statistics, sanitation work is one of the 10 most dangerous occupations in the country, and I learned why. You're in and out of traffic all day, and it's zooming around you. It just wants to get past you, so it's often the motorist is not paying attention. That's really bad for the worker. And then the garbage itself is full of hazards that often fly back out of the truck and do terrible harm. I also learned about the relentlessness of trash. When you step off the curb and you see a city from behind a truck, you come to understand that trash is like a force of nature unto itself. It never stops coming. It's also like a form of respiration or circulation. It must always be in motion. And then there's the stigma. You put on the uniform, and you become invisible until someone is upset with you for whatever reason like you've blocked traffic with your truck, or you're taking a break too close to their home, or you're drinking coffee in their diner, and they will come and scorn you, and tell you that they don't want you anywhere near them. I find the stigma especially ironic, because I strongly believe that sanitation workers are the most important labor force on the streets of the city, for three reasons. They are the first guardians of public health. If they're not taking away trash efficiently and effectively every day, it starts to spill out of its containments, and the dangers inherent to it threaten us in very real ways. Diseases we've had in check for decades and centuries burst forth again and start to harm us. The economy needs them. If we can't throw out the old stuff, we have no room for the new stuff, so then the engines of the economy start to sputter when consumption is compromised. I'm not advocating capitalism, I'm just pointing out their relationship. And then there's what I call our average, necessary quotidian velocity. By that I simply mean how fast we're used to moving in the contemporary day and age. We usually don't care for, repair, clean, carry around our coffee cup, our shopping bag, our bottle of water. We use them, we throw them out, we forget about them, because we know there's a workforce on the other side that's going to take it all away. So I want to suggest today a couple of ways to think about sanitation that will perhaps help ameliorate the stigma and bring them into this conversation of how to craft a city that is sustainable and humane. Their work, I think, is kind of liturgical. They're on the streets every day, rhythmically. They wear a uniform in many cities. You know when to expect them. And their work lets us do our work. They are almost a form of reassurance. The flow that they maintain keeps us safe from ourselves, from our own dross, our cast-offs, and that flow must be maintained always no matter what. On the day after September 11 in 2001, I heard the growl of a sanitation truck on the street, and I grabbed my infant son and I ran downstairs and there was a man doing his paper recycling route like he did every Wednesday. And I tried to thank him for doing his work on that day of all days, but I started to cry. And he looked at me, and he just nodded, and he said, "We're going to be okay. We're going to be okay." It was a little while later that I started my research with sanitation, and I met that man again. His name is Paulie, and we worked together many times, and we became good friends. I want to believe that Paulie was right. We are going to be okay. But in our effort to reconfigure how we as a species exist on this planet, we must include and take account of all the costs, including the very real human cost of the labor. And we also would be well informed to reach out to the people who do that work and get their expertise on how do we think about, how do we create systems around sustainability that perhaps take us from curbside recycling, which is a remarkable success across 40 years, across the United States and countries around the world, and lift us up to a broader horizon where we're looking at other forms of waste that could be lessened from manufacturing and industrial sources. Municipal waste, what we think of when we talk about garbage, accounts for three percent of the nation's waste stream. It's a remarkable statistic. So in the flow of your days, in the flow of your lives, next time you see someone whose job is to clean up after you, take a moment to acknowledge them. Take a moment to say thank you. (Applause)