In mid-February, nearly 200,000 individuals were ordered from their homes when Northern California’s damaged Oroville Dam spillway developed a hole after a major storm and threatened to flood the immediate area.
Now, as crews work to repair the flood control spillway, they’re faced with a new menace – naturally occurring asbestos.
According to an NBC Bay Area news report, work crews that are removing large amounts of rock, earth and other debris that washed to the base of the Oroville spillway last month recently discovered the mineral, which is actually fairly common in the California mountains and foothills.
The California Department of Water Resources said the asbestos was found in “limited areas” at the work site. Still, there is concern for the health of the many workers who are endeavoring to repair the dam.
Hence, officials have called in air quality control professionals to monitor the atmosphere around the work area to insure that the concentration of asbestos dust does not become too high.
“Crews repairing a damaged flood-control spillway have been using traditional construction methods such as wetting work areas with water trucks and laying rumble strips on roads to limit dirt collecting on equipment,” reported the Los Angeles Times.
They believe that the risk to workers is “minimal” and the risk to others in the area even lower.
Nonetheless, the state water department reported that they will consider increasing air monitoring as well as rock sampling if the need arises.
It’s just an extra aggravation as they work to maintain safe water levels in the reservoir and keep water flowing in the Feather River below the dam.
Workers are also addressing problems at a damaged hydroelectric plant at the site.
The U.S. Geological Survey continuously maps the locations of naturally-occurring asbestos as well as historical asbestos mines and former asbestos exploration projects.
About three dozen states have reported some naturally-occurring asbestos within their borders, with California having the most asbestos sites of the 50 states.
Other states that deal with a notable number of asbestos sites include Washington, Idaho, Alaska, Vermont, New Jersey, and other eastern states through which the Appalachian Mountains run.
Geologists note that fiber-rich minerals, like asbestos, are formed when magnesium and silica deposits are mixed with water and then super-heated by magma that’s rising up from the mantle below.
That makes certain locations – like mountainous areas – more likely to be the spots where naturally-occurring asbestos is found.