The elevated concentrations of chrysotile asbestos found at the repository indicate that the potential for inhalation exposures exists.  Because of the lack of vegetation and other surface water drainage issues associated with the dry retention basin, wind and surface water and mechanical erosion could eventually expose and damage the protective polyvinyl chloride (PVC) liner, which could expose the underlying asbestos-contaminated material and soil.  At the parking area, sections of the asphalt are settling and allowing surface water and sediment to accumulate.  The conditions of both areas of the repository increase the potential for the asbestos-contaminated soil to be released.

Exposure to airborne friable asbestos may result in potential health risks because persons breathing the air may breathe in asbestos fibers. Continued exposure can increase the amount of fibers that remain in the lungs. Fibers embedded in lung tissue over time may cause serious lung diseases, including asbestosis, lung cancer, or mesothelioma.

Refer to Polreps #1,  #2 and #3 for initial site inspection results that led to the removal actions before 2014.

Following the notification of these issues by the FBC to EPA, EPA's Superfund Technical Assessment and Response Team (START) contractor investigated the site in March 2014 and collected samples of the dry retention basin topsoil for soils testing. In August 2014, EPA returned to the site with its Emergency and Rapid Response Services (ERRS) and START contractors and met with representatives of the FBC to further assess these issues. Based on these March and August 2014 site inspections, EPA identified the following problems:
 

·        The settled areas of the asphalt allowed water and sediment to puddle near the engineered retaining wall;

·        Surface water did not drain properly from the asphalt parking lot through the dry retention basin and into the dry well;

·        Following hydroseeding in October 2012, a grass cover had never been established, and the dry retention basin was only sparsely vegetated;

·        The steep slopes at the northeastern of the retaining wall did not provide convenient access to the lower sections of the wall for maintenance and repair activities.

       .      The steep slopes along the asphalt at the southwest of the retaining wall were not graded,
             and represented a liability issue since people or vehicles could drive off the edge or get hurt. In addition, soil was eroding along the steep edge and out from under the asphalt, and, if not addressed could expose asbestos-contaminated soil.

ERRS and START contractors and EPA OSC mobilized to the site on Monday April 20, 2015.  START drove the EPA Region 10 communications rig to be used as the site's command post.  Equipment was also delivered on Monday to the site and set to promptly start the planned repairs (described below) on the repository on Tuesday morning.   

·        Repair the settled areas of the asphalt to allow for proper surface water drainage and to prevent surface water from ponding on the asphalt near the engineered retaining wall;

·        Establish vegetation in the dry retention basin by adding additional top soil and adding a new seed mix optimized for local climate conditions;

·        Reconstruct the surface details of the corrugated metal pipe around the dry well to allow for better drainage of surface water in the dry retention basin;

·        Add a gravel apron at the eastern edge of the dry retention basin to allow for better drainage of surface water from the asphalt parking area;

·        Construct ramps at the northeastern and southwestern edges of the retaining wall to allow for better access to the lower sections of the wall for inspections and maintenance.

Tuesday, April 21:

1.      Site work began with a general health and safety (H&S) meeting with all on-site staff. Safety meeting topics included a discussion of the planned phases of work and appropriate H&S procedures for each task. For excavation of contaminated soil under the asphalt area to be repaired, ERRS decided to use Level D personal protective equipment (PPE) based on the results of air sampling previously performed at the site in 2012 which indicated no sample results above the site action limits.

2.      After marking the area of asphalt to be replaced, ERRS cut it with a saw and broke it up into smaller pieces.  Excavated soil and asphalt were direct-loaded to the haul trucks to avoid stockpiling material outside of the trench, and to keep the broken pieces of asphalt and the excavated soil within the footprint of the asphalt repair area to minimize the spread of any contaminated material. The asphalt sub-base layer and contaminated soil was excavated to a target excavation depth of approximately 3 feet below ground surface (bgs).

3.      One truck hauling a trailer and a pup trailer transported the excavated material off site to the Finley Buttes Landfill in Boardman, Oregon.  Prior to loading the waste, ERRS lined the beds with an outer woven geotextile exterior liner material, followed by a 6-mil visqueen inner liner between the soil and the woven geotextile, so that the load can be completely wrapped for transportation (i.e., a "burrito wrap"). 

4.      Four truckloads (135 tons) of the top soil (50%/50% blend of soil and Eko compost from Lewiston, Idaho) was delivered to the site and ERRS began to spread it around the dry retention basin with the wheeled mini-loader.

5.      START performed air monitoring and sampling. Three DataRAM particulate monitors with data loggers were placed around the perimeter of the site to monitor for airborne dust, and the results were well below the site action level for dust of 1 milligram per cubic meter (mg/m3). START also collected three air samples, including two perimeter air samples around the excavation area and one personal sample from the cab of the mini-excavator.

6.      The OSC met with Pastor Hale Anderson of the FBC to coordinate the site activities and discuss future post-removal site controls for which the FBC will be responsible.

Wednesday, April 22:

1.      Five trucks/pups loaded with the broken pieces of asphalt and contaminated soil were loaded and transported to the landfill.

2.      Two truck loads (64 tons) were delivered to the site, for a final total of approximately 200 tons of top soil added to the dry retention pond.

3.      The top soil around the CMP was removed with shovels down to the PVC liner between the contaminated soil and the top soil.  The CMP was cut so that it was flush with the level of the PVC liner, and rubber hose was installed on the edge of the CMP to prevent damage to the PVC liner from the sharp edges. The PVC liner was folded down the inside of the CMP and the gravel replaced inside the CMP.

4.      ERRS continued to spread and lightly compact the top soil on the dry retention basin with the skid steer.

5.      ERRS also began to excavate top soil along the border with the asphalt parking area to prepare for the installation of the gravel apron.

6.      START deployed the DataRAM dust monitors, and the results were well below the site action level.

7.      Representatives from the National Resource Conservation Service (NRCS) office in Orofino visited the site to consult with EPA. NRCS had recommended the local seed mix that will be used to re-vegetate the dry retention basin, and NRCS visited the site to provide additional recommendations related to establishing a vegetative cover in the dry retention basin. The NRCS representatives also volunteered to visit the site every few weeks for several months following the removal action to monitor the progress of the newly seeded lawn.

8.      A START engineer arrived on site on Wednesday afternoon to participate in the removal action and to assist ERRS in implementing the project design developed by START.

Thursday, April 23:

 1.      Five trucks/pups were loaded with the waste material (asphalt and contaminated soil) and transported to the landfill.

2.      The excavation of the western section of the asphalt repair area was completed (depth of 3 feet bgs) and backfill began in the area with a ¾-inch minus sub-base material. Prior to backfilling, a nonwoven geotextile was laid down at the bottom of the excavation area and on top of the underlying contaminated material. The ¾-inch minus backfill material was then placed and compacted in 6-inch lifts.

3.      One load of 1.5-inch drain rock and one load of 2- to 4-inch drain rock were delivered to the site to be used for the gravel apron and the drainage area around the dry well. 

4.      The reconstruction of the CMP was completed and washed drain rock was placed around the dry well and CMP.

5.      A riding sweeper machine was delivered to the site to clean the parking lot.

6.      START performed dust monitoring with the DataRAMs, and the results were all less than the site action limit. START collected three air samples from the work zone, including two perimeter and one personal, which will be submitted to an off-site laboratory for PCM testing.