In addition, the report said, toxic agents that are not monitored, but which are suspected of causing disease, include pollutants like PCB's and dioxin, dangerous metals like mercury and lead, and pesticides. The Environmental Protection Agency sets limits on how much of some of these substances can be put into the environment, but it dos not track them and try to link their effects to human diseases. An example of the failure to monitor chronic diseases and possible environmental causes was the case of Libby, Mont., the report said. In that town of 2,700, an epidemic of respiratory diseases, including asbestosis, unusual cancers, and emphysema, has been unofficially noted for decades. Only this year did a federal investigation find that a vermiculite mine not far away had been releasing tons of tremolite for 50 years.
Tremolite is a natural but rare and highly toxic form of asbestos.
Investigators estimate that 200 residents have died from diseases associated with the substance, and many more are ill.