Diesel exhaust has been identified as a likely or known carcinogen. Research is coming to the forefront that shows exposure to diesel fumes increases the risk of cancer.
The deadly effects of breathing diesel fumes came into sharp focus in 2005 when the Clean Air Task Force (CATF) released a report estimating that diesel fumes kill about 21,000 U.S. citizens each year.
Furthermore, diesel fumes cause 27,000 non-fatal heart attacks and 410,000 asthma attacks in U.S. adults each year, plus roughly 12,000 cases of chronic bronchitis, 15,000 hospital admissions, 2.4 million lost-work days, and 14 million restricted activity days.
And that is almost certainly not the worst of it. The Clean Air Task Force report cites numerous studies revealing that diesel soot:
A study by the Natural Resources Defense Council (NRDC) found that levels of diesel exhaust on four Los Angeles school buses were eight and a half times higher than average levels found in California's smoggy air. This was four times higher than the fumes from inside a car driven directly in front of the buses. NRDC researchers measured diesel exhaust levels during five hours of tests conducted on actual bus routes in the city.