Amid the crisis, two top state air regulators have resigned, residents are rushing to the doctor to get tested, and politicians in this city of 600,000 are scrambling to do damage control.
Air pollution hot spots with high levels of cadmium, arsenic and chromium were detected recently around two makers of colored glass.
Long-term exposure to such substances is linked to lung and bladder cancer, kidney disease and other ailments.
Smaller glassmakers such as Bullseye Glass and the other business under suspicion, Uroboros Glass, are exempt from U.S. Environmental Protection Agency regulations governing heavy metal emissions.
Linda George, a professor of environmental sciences at Portland State University, said that when it comes to heavy metals, the EPA essentially tells states, "You decide on your own what risks you're willing to tolerate and you decide on your own benchmarks and how you're going to reduce risks."
EPA officials declined requests for an interview but said in a statement that the federal Clean Air Act gives state and local agencies the lead role in regulating such substances and "provides much flexibility to states so that their programs can reflect local situations and needs."