Some Dirty Rotten Rumors about New Idria

There are many opinions regarding pollution and environmental hazards at Idria and it therefore becomes impossible to give fair audience to such a difficult topic. On this page, we attempt to at least relate the gamut of opinion by dividing them into two broad statements, expressed below as "Opinion A" and "Opinion B."

Opinion A

Click here to read Opinion B

There is a popular misconception held by a few people that the New Idria mine site is an Environmental Protection Agency (EPA) Superfund site. This thought is simply incorrect.

The New Idria Mercury Mine became listed in the EPA's Comprehensive Environmental Response, Compensation, and Liability Information System (CERCLIS) database on April 16, 1996 (CA0001900463). However, the EPA determined that the property does not qualify for inclusion in the National Priorities List (NPL, i.e. "superfund"). The EPA listing in the CERCLIS database is because this was the location of the world's fourth largest quicksilver mine. The EPA listing in the CERCLIS database is often interpreted as meaning "superfund list." Certainly, it easy to understand this misinterpretation, especially when it concerns distressed property. However, Joan Simmons, CERCLIS/SUPERFUND FOIA Coordinator assured us that New Idria "is not a superfund site; Only sites on the National Priorities (NPL) list are designated as such." This opinion was also recently reinforced by Carolyn J. Douglas, a scientist with the U.S. EPA Region 9 in San Francisco.

Regardless, there are some environmental issues associated with this property because it was a cinnabar mine and a mercury processing plant for about 115 years.


Acid Mine Drainage (AMD) from Adit 10. The red color is from iron oxide in the water (not mercury). While it certainly looks horrible, it is not dangerous.

While there has been a good deal of study and concern about these pollution problems, little has been done to begin remediation for several reasons. The primary reason is simply the lack of funds to pay for the cleanup. While some experts think that the threat, and therefore the required cleanup, is minimal, there is another school of thought that debates the magnitude of the environmental and economic threats. See Mercury Contamination in Prospective for more information.


The Settling Pond for the AMD from Adit 10 has not been maintained in more than thirty years and no longer allows water to rest here long enough for the iron oxide to settle out before draining into San Carlos Creek.

The EPA awarded San Benito County a $200,000 Brownfields Assessment Grant in 2004. That money was expected to be used to "develop a remediation plan and risk assessment" for the New Idria Mine and for development of site use alternatives, and community involvement. However, the money appears to have gone elsewhere.

Regardless of the debate about the potential pollution of an isolated segment of the property, the fact remains that the area is already a registered historical site. That fact alone speaks loudly for its preservation. Factor in the known natural and cultural resources and we are presented with a valuable resource that needs to be protected, cleaned up, preserved, and enjoyed.

Click here to read Opinion B

Environmental Issues at Idria
Mercury Contamination in Prospective
Acid Mine Drainage in Prospective

EPA Answers
Superfund Information Systems
What is a Superfund site?
What is the National Priorities List?

About AMD
What is AMD?
AMD and Passive Treatment
Controlling AMD

Copyright ©, 2005 Three Rocks Research. Update: December 30, 2006