Ordinary waste, not specifically classified as hazardous, is defined by the EPA as any garbage, refuse, or sludge from a wastewater treatment plant, water supply treatment plant, or air pollution control facility, and other discarded material. Discarded material includes solid, liquid, semi-solid or contained gaseous material resulting from industrial, commercial, mining, and agricultural operations, and from community activities.
Waste is hazardous when it is ignitable, corrosive or reactive (explosive). Also, if waste contains certain amounts of toxic chemicals, it is considered hazardous. In the Butte area, hazardous substances include mine tailings that are rich in toxic chemicals like arsenic and heavy metals, and ground and surface water impacted by mine waste, which then becomes acidic and potentially corrosive.
There are 500 specific hazardous wastes as defined by the EPA. For more information, read the Office of Solid Waste’s fact sheet, What Makes a Waste Hazardous? on the EPA’s website.
People are exposed to hazardous substances in several ways:
- contaminated air;
- direct contact with hazardous waste;
- contaminated drinking water;
- fire or explosion;
- the food chain;
- contaminated ground water;
- contaminated soil; and
- contaminated surface water.
The sources of exposure vary depending on the site, and not all of these exposure threats exist at every site. That’s why EPA scientists must assess a site and figure out the type of exposure threats that exist. Once they know that, the best way to protect the health of the surrounding community and environment can be determined and the cleanup can begin. In addition to human health, the EPA considers impacts to the environment and wildlife (particularly endangered species).
In the case of Butte, hazardous waste exposure can potentially occur through contact with exposed mine tailings, drinking water contaminated by contact with mine waste, the food chain, contaminated ground water, contaminated soil, or contaminated surface water.
For more information on hazardous waste exposure and risks in the Butte area, visit the Public Health page.