New Yorkers' risk of developing cancer from air toxins is estimated to be 68 residents per million. In California, the risk is 66 residents per million.
The national average is 41.5 per million, according to the report, which was released in February and based on emissions of 177 chemicals in 1999, the most recent data available.
Oregon, Washington, D.C., and New Jersey had the third, fourth and fifth worst air in the nation, respectively, the EPA said. Rural residents of Wyoming, South Dakota and Montana breathed the cleanest air.
The EPA assessment evaluated toxins including heavy metals, such as lead; volatile chemicals, such as benzene; combustion byproducts, such as acrolein; and solvents, including perchloroethylene and methylene chloride.
Benezene alone contributed a quarter of the individual cancer risk identified in this assessment, the primary source of it being vehicles, according to the study.
The National-Scale Air Toxics Assessment (NATA) is a screening tool that estimates cancer and other health risks from exposure to air toxins. It provides a snapshot of air quality and the risks if 1999 emissions levels remained unchanged. It does not reflect reductions in air toxins that may have occurred since 1999.