Diesel exhaust, which is common on construction sites due to the prevalence of heavy equipment and trucks, causes lung cancer and may increase the risk of bladder cancer, says the International Agency for Research on Cancer, which is part of the World Health Organization. The agency announced the new health risk on June 12.
Diesel advocates counter that modern regulations have brought emissions to near-zero levels. Though WHO recognizes this, it says that "while the amount of particulates and chemicals are reduced with these changes, it is not yet clear how the quantitative and qualitative changes may translate into altered health effects." WHO calls for further study.