Oroville Dam: Asbestos found in spillway rock; dust controls increased

Oroville – Naturally-occurring asbestos has been found in the rock formations and in the air near the damaged Oroville Dam main spillway, according to a press release.

Although California Department of Water Resources said risk to workers and the surrounding community is minimal, dust-control operations are being increased. Air quality will continue to be monitored at the work site and nearby neighborhoods.

Bob McLaughlin, Butte County Air Quality Management District assistant air pollution control officer, said because some air quality tests came back positive, the area is being treated like a contaminated site.

“Absolutely any time there’s potential for public exposure to asbestos it’s a concern,” he said. “It’s either there, or it isn’t. If it’s there, you do everything you can to minimize dust emissions. You have to assume it’s everywhere (at the site). … You need to be very diligent and proactive in protecting public health.”

California Department of Water Resources said it was discovered in “limited areas” during the debris removal operation, and will be addressed “safely and successfully” with standard operating procedures.

The common mineral is found all over California, in 42 of its 58 counties, according to the Environmental Protection Agency. Serpentine, which contains asbestos, is actually the state rock.

Asbestos is a human carcinogen, however, and can cause lung cancers, including mesothelioma, if airborne asbestos fibers are inhaled. It’s for this reason that naturally occurring asbestos can be a cause of concern if it is crushed or similarly disturbed.

“Out of an abundance of caution,” DWR has submitted a dust-control and air monitoring plan to the Air Quality Management District.

Control measures already in place include wetting the soil, using wet drilling methods and utilizing rumble strips on roads to reduce dirt collection on heavy equipment. Plans include washing trucks and tires, using personal air monitors and increasing how many air samples are collected.

 

DWR said it will continue to work with air quality officials, geologists and safety officers to monitor risks as work continues.

McLaughlin said the Air Quality Management District is working with DWR on additional monitoring to determine if there are “ambient levels of asbestos that would be a concern.” DWR is doing everything they can to minimize dust emissions, he said. The Air Quality Management District’s role is to protect the public, and they will make sure DWR and contractors are proceeding cautiously and operating under state-required airborne toxic control measures.

If people have concerns or see an excess of dust in the area, they can contact the Butte County Air Quality Management District at 1-855-332-9400.

There is a county air monitor located by the staging area, providing a live update of emissions in the area at bcaqmd.org. Though that only includes information about dust levels, not asbestos.

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Meanwhile, the damaged main spillway is expected to brought into use sometime Friday. DWR has scheduled a 9 a.m. press conference on the matter.

The spillway has been shut down since Feb. 27, after Lake Oroville had been drawn down more than 50 feet from the emergency spillway lip. Crews working on the debris pile that built up at the base of the spillway have removed 1.24 million cubic-yards of material as of Thursday morning, according to DWR. The pile was originally estimated at 1.7 million cubic-yards.

Releases from Lake Oroville through the Hyatt Powerhouse remain at 12,900 cubic-feet per second, while inflows are fluctuating in the neighborhood of 19,000 cfs.

As a result, the lake level continues to rise, and was at 863.49 feet above sea level at 5 p.m. Thursday. That’s an increase of about 8 1/2 inches in 24 hours.

The flow in the part of the river past Oroville was increased from 10,700 cfs to 13,700 cfs Thursday afternoon, according to DWR, and releases from the Thermailto Afterbay outlet were shut off.

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