$21 million Oak Ridge renovation under way
California requires school districts launching construction projects to remove and cover naturally occurring asbestos in soil disturbed by the projects. The aim is to minimize the release of asbestos.
“We believe that the precautions we are taking right now [at Oak Ridge] and the dust mitigation measures are adequate to reduce the possibility of asbestos getting in the classrooms,” said Bud Duke, senior engineering geologist at the state Department of Toxic Substances Control, an arm of the California Environmental Protection Agency.
Duke’s agency is overseeing the Oak Ridge project, which also requires the school to be fenced off and sealed before renovations begin.
The school is adding 19 classrooms, moving some portable classrooms and replacing six others. The school also is adding a new music classroom on the current amphitheater site, a new multipurpose building and new campus walkways.
The project began May 27. About 1,000 cubic yards of soil are being removed between June 1 and Aug. 11. A public work notice was distributed on May 20 to residents within a quarter mile of the site as well as parents of Oak Ridge and feeder school students.
Asbestos was originally discovered at the school in 2002 when white veins exposed in construction of soccer fields turned out to contain tremolite and chrysotile asbestos concentrations up to 8.8 percent by weight.
The state hasn’t established a threshold for what’s considered dangerous in soil naturally occurring concentrations, but according to DTSC’s Oak Ridge project manager, Michael Hall, the state Hazardous Waste Control Act considers 1 percent concentrations in manmade waste hazardous.
According the California Department of Toxic Substances Control, all forms of asbestos can cause serious health problems, including respiratory disease and cancer from inhaled fibers.
Naturally occurring asbestos is commonly found in the ultramafic and serpentine rock formations throughout El Dorado Hills. Asbestos is released and becomes potentially hazardous when the rock is crushed or broken.
The project site consists of six separate areas, totaling approximately 3.2 acres of the existing 49-acre high school campus.
A draft Removal Action Work Plan for the Oak Ridge site was presented to parents and school officials in January. The plan has since been finalized.The excavation and covering of the soil containing naturally occurring asbestos began on Tuesday, May 27, and is expected to take approximately eight weeks to complete. The field work will be conducted between 7 a.m. and 7 p.m. Monday through Friday, and between 8 a.m. and 5 p.m. Saturday and Sunday but was suspended June 7 when the SAT test was administered at Oak Ridge.Once the soils are excavated and covered, construction of the buildings can begin.Soil movement through EDHAbout 16 trucks filled with NOA soil will be transported off site every day for seven to 12 days during the project. Trucks entering the Oak Ridge site will take Highway 50 to El Dorado Hills Boulevard, and travel two miles north to Harvard Way to the site. Trucks exiting the property will follow the same route in reverse. About 40 total truckloads of clean soil will be imported along the same route.
All unearthed soils will be covered with a protective “geotextile fabric” and topped with at least six inches of clean soil in areas not otherwise covered by a building, parking lot or walkway.
Building walls closest to the work zones will be covered with plastic. Windows, doors and air conditioning units on portable classrooms will be covered to create a dust barrier. Block buildings will have windows and doorways sealed on sides adjacent to the work zones.
Air circulation is required in block buildings to prevent mold. Air conditioning will only be turned on during nonworking hours, and air filters in the classrooms will be changed before school begins.
All buildings, patios, parking lots and athletic field bleachers will be hosed down when the NOA soil excavation is complete. Where runoff enters storm drains, sediment will be collected in filter bags installed in drain inlets.
The interiors of all buildings on campus will be cleaned using DTSC “Best Housekeeping Practices,” which include wet wiping all horizontal hard surfaces. Curtains, fabric window treatments, upholstery and other materials that cannot be cleaned by wet wipe methods will be HEPA vacuumed twice.
Fabric covered furniture will be vacuumed using a stiff brush attachment. Classrooms furthest away from the work zones will be cleaned first then sealed. Cleaning will progress toward the classrooms closest to the work zones throughout the summer.
Classrooms within the work zones will be cleaned after the soil excavation and capping, but prior to the start of school. The administration and counseling buildings will be cleaned during the first two weeks of July. No office staff or faculty will be allowed on campus during that time. Classroom cleaning will be coordinated by the district.
DTSC will perform a visual walk-through after cleaning to verify the cleaning.
Outdoor air and dust monitoring will be conducted inside each work zone at the upwind and downwind boundaries, and downwind of the zone.
Air monitoring results will be placed on the DTSC EnviroStor database promptly, and can be viewed online at www.envirostor.dtsc.ca.gov/public/profile_report.asp?global_id=09820001.
No indoor air monitoring is planned, a fact which raised the ire of several parents and teachers during the January meeting.
DTSC officials reached by phone last week said that the results of the outdoor air testing would be evaluated on a week-to-week basis, and that indoor testing would be conducted if outdoor asbestos levels were high.
“The chances of anything getting through all that plastic into those classrooms are slim to none,” said project manager Hall. “I just don’t see that happening.”
Parents and teachers in the January workshop were also concerned that soil with NOA could blow into the adjoining neighborhoods on windy days.
Bud Duke, senior engineering geologist at the Department of Toxic Substance Control, said that the department’s guidelines call for stopping work whenever winds caused visible dust to extend 25 feet beyond the project boundaries. “Our intent is to stop well before it gets to that point,” he said.
Water trucks will be used to lightly spray the soils before and during earthwork to prevent dust from becoming airborne. Stockpiled soils will be covered. Truck tires and equipment leaving the site will be cleaned to remove soil and debris.
Truck loads will be covered. On weekends, exposed NOA soils will be crusted, wetted or covered. All visible dust within 25 feet of the work zone fence line will be removed.
No student activities have been scheduled on the Oak Ridge campus during the summer of 2008, with the exception of Scholastic Aptitude Testing June 7. Students taking the SAT exam were confined to the small gym and the west parking lot.
Students and faculty will not be allowed within the work zone until soil excavation and capping is completed. Workers within the work zones will wear safety gear.
At the conclusion of the summer 2008 soil removal, DTSC will update the community on the status of the project and classroom cleaning activities.
For more information on the soil removal activities and schedule or air monitoring results, contact Bud Duke, DTSC project manager, at (916) 255-3695 or by e-mail to BDuke@dtsc.ca.gov.