It's the odor of a burning computer. Or a burning tire. Or burning paper. One person said it was the scent of unsettled souls.
It's the smell, once overwhelming, now increasingly ephemeral, that emanates from the tangled wreckage of the World Trade Center.
It has become an elusive smell. The first days after the collapse of the towers, it was so pungent that shifting winds transported it for miles, all the way to the upper reaches of Manhattan. They carried it over into Brooklyn and Queens, deposited it in New Jersey. Everyone seemed to smell the horror of death.
Nearly three weeks later, the smell is more localized, but still there, a stubborn reminder. Depending on the strength and direction of the wind, the odor might be evident three blocks east of the remains but not three blocks west. You might smell it north of the site but not south. On certain days, people as far away as Greenwich Village, if not farther, say they can sniff it.
On Friday, it was particularly potent in the crowded Wall Street area. "As the days wear on, it's gotten better," said Gus Albano, a clerk at the New York Stock Exchange. "But it got worse today for some reason. It was almost like the early days, when my stomach turned from the smell."
What did it smell like? "Like a rubber tire burning," he said.
Some workers in the financial district went home early on Friday because they found the smell so repugnant. One firm on Broad Street, which didn't want its name used, said most of its employees chose to leave by 1pm, complaining that they couldn't concentrate because of the foul odor, and, city disclaimers to the contrary, they feared that it might be noxious.
The smell seeped inside the offices, even though the windows were shut and the air-conditioning vents had been cleaned.
"It's like burning plastic, or what a burning computer might smell like," said a woman who works at the firm. "Yesterday, it was fine. I don't remember smelling it too much then. It changes day to day. But today it was awful. People said the smell brought back horrible memories."
Even though people were complaining about the smell and fretting over what it signified about the air, hardly anyone except rescue workers and some police officers has bothered to wear a respirator mask in recent days.
On the morning the stock exchanges reopened, masks were omnipresent downtown.
The other day, they were rare. A few people had their jacket collars pressed against their noses. Others had tied handkerchiefs around their faces, bandit style. One young man simply pinched his nose with his fingers as he walked. A middle-aged woman had folded an American flag over her mouth.
City and federal officials have been continually testing the air near the fallen towers, and they have consistently maintained that the air is safe to breathe. That is enough for some people. That is not enough for many others who worry about toxins and even asbestos.
"It's very bad, golly, it's so bad," said Rob Smith, 45, a telecommunications engineer from Virginia who was working in the financial district on Friday. Walking on the street, he had a handkerchief covering his nose and mouth.
"Some days it's better, some days it's worse," he said. "On a scale of 1 to 10, today is about 7. It smells like rubber burning. Some days it's like metal burning. Other days it's like paper burning. Today is rubber."



