Forest Closes Location of the Historic Big Blue Mill Site to Public Access

The Sequoia National Forest has closed the Historic Big Blue Mill Site (Site) due to elevated levels of heavy metals that were determined to be a potential risk to public health.

The Site is located along the western shore of the Kern River, approximately 2 miles upstream of Lake Isabella.  The mill is a former gold ore processing facility dating back to the 1860s that was associated with the nearby historic Big Blue and Sumner group of mines.

The Forest Service has completed a Comprehensive Environmental Response Compensation and Liability Act (CERCLA) Preliminary Assessment (PA) and Site Inspection (SI) at the Site and the links to those reports are shown below.

Elevated levels of arsenic, lead, antimony, and mercury have been detected in the soils and mill tailings at this Site, which greatly exceed naturally occurring/background levels and established human health risk screening thresholds.  The presence of these elevated heavy metals presents a potential exposure hazard to site visitors and nearby residents.

Due to the potential public health risks associated with the Site, Forest Supervisor Teresa Benson has closed the area to the public.

For more information regarding the area closure order, please email District Ranger Alfred Watson at

The Forest Service will be conducting an Engineering Evaluation/Cost Analysis (EECA) this Fall/Winter to evaluate Removal Action alternatives to reduce the risk of exposure to human health and the environment. 

For information regarding the Forest Service’s site investigation efforts, please email Regional On-Scene Coordinator, Noelle Graham-Wakoski at