In 2000 and 2001, EPA Region 10 and its START contractor conducted two visits to the former Vermiculite Northwest vermiculite processing facility that included sampling and analysis. The initial visit in 2000 was to determine if asbestos existed in soils or on surfaces at the Vermiculite Northwest property located at 1318 North Maple Street, Spokane, Washington. Eight bulk soil and wipe samples were collected. All samples contained from trace amounts to 2% total asbestos fibers. In 2001 the START contractor was tasked to conduct a removal site evaluation at the facility. The START collected 27 soil samples, which included 14 samples taken from residential locations surrounding or otherwise associated with the Vermiculite Northwest property. Four of the residential area samples showed trace levels of asbestos.
In 2002 through 2005, Spokane County demolished, removed and disposed of buildings at the former Vermiculite Northwest processing facility that contained asbestos. In 2006, Spokane County conducted a study (through a contractor) to identify the vertical extent of asbestos contamination is soils in the former vermiculite processing area. The study found asbestos present in significant concentrations at depths greater than four feet. As a result, Spokane County and Washington Department of Ecology concluded that encapsulation of asbestos contaminated soils in place, at least in the fairly level southwest quadrant of the facility where asbestos contaminated soils were deep, was a more feasible alternative than removal and disposal. In 2007, Spokane County developed a design and completed work on an asphalt and soil cap and cover over the southwest quadrant of the facility, where the former vermiculite processing and handling buildings were previously located, where the highest concentration of asbestos was found in soils, and where asbestos was found to occur at depth.
In 2009, EPA Region 10 determined that additional information was needed on possible migration of asbestos fibers from the former Vermiculite Northwest processing facility to surrounding residential properties. Processing vermiculite is an industrial process that generates dust, including asbestos fibers, that could become airborne and potentially impact surrounding residential properties located adjacent to and/or downwind from the former vermiculite expansion plant. The sampling approach involved a phased assessment, consistent with EPA’s Strategy for Further Assessment of Vermiculite Ore Asbestos Sites. The phased assessment included bulk soil sampling, laboratory-based testing, and activity-based sampling. Bulk soil sampling was conducted at nine residential properties surrounding the former processing facility. Results showed trace levels of Libby-type amphibole asbestos (that may be associated with the former Vermiculite Northwest processing facility) in all but two of the samples (“trace” level is below the quantifiable method detection limit, but still observed in the sample). Quantifiable levels measured at 0.25% amphibole asbestos were detected at two residential properties, one of those locations being an apartment complex property at 1518 W. Sharp Avenue, which is directly south of the former Vermiculite Northwest processing facility and where some of the highest asbestos concentrations were found on the facility property (which is now under asphalt cap).
Region 10 followed up bulk soil sampling and CARB 435 method analysis with analysis using a fluidized bed asbestos segregator. The fluidized bed is currently experimental, but is expected to be capable of detecting very low concentrations of asbestos in soils that may become airborne, by “fluidizing” the soil fines in a stream of air where small particulates are drawn from the air flow and deposited on a filter, which is then analyzed via transmission electron microscopy (TEM). The fluidized bed results showed a significant concentration for Libby-type amphibole asbestos from only one residential sample, the sample from 1518 W. Sharp Avenue.
Finally, in September 2009 Region 10 conducted activity-based sampling (ABS) at two residential properties, as well as on Spokane County-owned property that used to be part of the Vermiculite Northwest facility. The intent of ABS is to determine if asbestos fibers present in the soils, even at very low concentrations, could become airborne and present a risk of inhalation through normal soil disturbing activities. One of the ABS residential sample locations was the property other than 1518 W. Sharp Avenue that had shown a quantifiable concentration (0.25%) from the CARB 435 method analysis. The other residential location exhibited a “trace” level. The property at 1518 W. Sharp Avenue was not tested using ABS because most of it is a paved parking lot, and exposed soils are primarily in planting areas between the parking lot and the apartment complex. This area did not lend itself to ABS because of the relatively small, separate locations of the several planting beds.
The property is directly south of the former Vermiculite Northwest vermiculite ore exfoliation processing facility. There is an alleyway that separates the north part of the residential apartment complex property from the part of the former Vermiculite Northwest facility where some of the highest concentrations of asbestos were found in soils, prior to capping. The area of the property that is of concern is the north part of the property, between the apartment complex building and the alleyway. This part of the property largely consists of an asphalt parking area for the apartment tenants, but there are is a planting area with exposed soils. These soils exhibited elevated concentrations of Libby-type amphibole asbestos consistent with asbestos related to the former Vermiculite Northwest facility.
EPA conducted a removal action in April, 2011 to remove and properly dispose of asbestos contaminated soils from planting beds at 1518 W. Sharp Avenue, and replace with clean soils. The total estimated volume of soils removed was approximately 13 cubic yards. Air samples will be collected during soils excavation to provide data regarding any possible migration of asbestos fibers in air as a result of the removal activity.