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Formosa Mine

This site spans 76 remote acres on Silver Butte in Douglas County, about 25 miles south of Roseburg.

Mining activities dating back to 1910 have released heavy metals and acid mine drainage into the headwaters and south fork of Middle Creek.

After mining operations stopped in 1993, the mine was filled with mill tailings, crushed ore and limestone. The Formosa Corporation filed for bankruptcy shortly thereafter and abandoned the mine.

The mine continues to contaminate these waterways, where stream habitat has been severely degraded.

  • In 2000, the Oregon Department of Environmental Quality (DEQ) installed a water diversion system to keep acid mine drainage out of the stream.
  • In 2007, the Formosa Mine site was added to the Federal Superfund program's National Priority List (NPL), mainly due to environmental degradation.
  • In 2008, the Environmental Protection Agency (EPA) cleaned and repaired the diversion system, to keep contamination to a minimum until a permanent solution can be found.

EHAP Investigation

The Environmental Health Assessment Program (EHAP) investigated whether or not this site would put the health of humans at risk. The report concludes that no public or private drinking water systems are affected by the acid mine drainage, but drinking or bathing in the water directly downstream from the mine is a health hazard. The water is very acidic, so even getting it on your skin should be avoided.

How did EHAP become involved at Formosa Mine?

EHAP is in a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR), which is mandated by congress to complete a Public Health Assessment at superfund sites within one year of them being listed. EHAP carries out ATSDR's mandate in Oregon. Public Health Assessments try and answer the question, "Will I get sick?" from the site's contaminants. EHAP makes every effort to understand the human health risks and concerns of communities that live nearby.


Public Comment Period

EHAP solicited public comments until August 1, 2009.  Comments received were incorporated into the final version. No conclusions or recommendations were changed between versions.

Public Participation

EHAP accepted public comments and incorporated them into the final version of the public health assessment (above)

Related Websites

formosa mine