Jeffrey Smith was a sales director working just over a block from the Twin Towers when terrorists attacked 20 years ago. He laments the lesser-known death toll that has followed 9/11, such as those caused by the toxicity of the air: “I got a four-element mask, you know, optimized to the dangers … I ended up on 14 medications anyway … The fumes in our office destroyed both the oils and acrylic paint. So what is that doing to people?” Nejan Paniagua came from Cyprus as a young woman to study in New York. Twenty years later, visiting Ground Zero, her mind is still inscribed with the same scene of devastation she saw back then: “It was like a war zone. Everything was collapsing. People were running. [There was] dust everywhere. It did smell like burning flesh and wires. It was thick smoke. A lot of big stones. It did …