"The site was hot for months. The metals burned into fine particles. They rose in a plume and moved over people's heads on most days. There were at least eight days when the plume was pushed down into the city. Then people tasted it, smelled it and saw it. But people who worked in the pile were getting it every day. The workers are the ones that I worry about most," Cahill told The Chronicle.

Cahill's data found that the pollution included very fine metals, which interfere with lung chemistry; sulfuric acid, which attacks lung cells; carcinogenic organic matter; and very fine insoluble particles such as glass, which travel through the lungs and into the bloodstream and heart.