W.H.O. Declares: Diesel Fumes Causes Lung Cancer

Diesel fumes cause lung cancer, the World Health Organization declared Tuesday, and experts said they were more carcinogenic than secondhand cigarette smoke.

The W.H.O. decision, the first to elevate diesel to the “known carcinogen” level, may eventually affect some American workers who are heavily exposed to exhaust. It is particularly relevant to poor countries, where trucks, generators, and farm and factory machinery routinely belch clouds of sooty smoke and fill the air with sulfurous particulates.

The United States and other wealthy nations have less of a problem because they require modern diesel engines to burn much cleaner than they did even a decade ago. Most industries, like mining, already have limits on the amount of diesel fumes to which workers may be exposed.

The medical director of the American Cancer Society praised the ruling by the W.H.O.’s International Agency for Research on Cancer, saying his group “has for a long time had concerns about diesel.”

The cancer society is likely to come to the same conclusion the next time its scientific committee meets, said the director, Dr. Otis W. Brawley.

“I don’t think it’s bad to have a diesel car,” Dr. Brawley added. “I don’t think it’s good to breathe its exhaust. I’m not concerned about people who walk past a diesel vehicle, I’m a little concerned about people like toll collectors, and I’m very concerned about people like miners, who work where exhaust is concentrated.”

Many studies have suggested links between diesel and lung cancer, but Dr. Silverman said hers was the first to measure with precision how much diesel exhaust each group of mineworkers was exposed to. Her study clearly established that the more a miner was exposed to diesel, the greater his cancer risk, she said.

“Now we need to focus on managing exposures to diesel exhaust,” Dr. Brawley said.