On Tuesday August 21, 2007 the USEPA's Emergency Response Unit responded to and confirmed reports that a release of suspected historic contamination had been encountered during excavation activities at the former Taylor Lumber facility located at 22100 Rock Creek Rd. in Sheridan, OR.
The former Taylor Lumber site is currently undergoing site remediation under the direction of the USEPA's remedial program.
OSC Dan Heister responded to the incident on Tuesday evening. Heister confirmed the presence of potential historical contamination and requested assistance from EPA's Emergency Response Unit.
The following morning, OSC Marc Callaghan (2) START, and (4) ERRS personnel arrived on site to: 1) prevent the released materials from reaching navigable waters of the US and 2)investigate the potential source of the spill.
START members conducted a site survey and found visible contamination beginning in the culvert inlet on the north side of the highway and ending roughly 40-feet south of the culvert outfall on the south side of the highway. START found no evidence to suggest the contaminants reached the river and found no evidence of contaminants in any other drainage leaving the south side of the site.
An "oily" substance was encountered by a backhoe operator while performing excavation operations as part of their existing remediation statement of work.
The substance was first observed in a ditch which runs along the eastern boundary of the site, parallel to SW Rock Creek Rd. The oily substance was later encountered during continued backhoe operations, while digging on the opposite end of a culvert which runs north-south under the Willamina-Sheridan Highway (Highway 18-buisness loop) towards the Yamhill River.
Based on verbal reports from it appears several layers of contamination were discovered. The first layer was encountered approximately 6 inches below the native ditch surface. This lens reportedly extended North from the highway approximately 20 feet and was 3 inches thick (depth). It was described as a thick creosote like material that was rubbery and not very mobile. This layer is not suspected to be the layer which caused the sheening. The source of more mobile material appears to have been encountered after the contractor excavated through a confining clay layer (greater than 2 feet bgs) and began encountering larger cobbles. The contractor appears to have breeched the confining clay layer in 4 places; (3) North of HW 18 and at the culvert outflow on the South side of the hwy.
The lense of creosote (3”deep X 20feet long X 2 feet wide) discovered nearer the surface appears to have been fairly limited. The magnitude of the more mobile contamination in the deeper cobble layer could not be quantified. It is suspected that this is historic spillage.
Emergency Response Objectives were directed at:
(1) preventing contamination from entering waters of the US
(2) mitigating the source of the release
(3) ensuring ER activities did not impeded, any activities being conducted by the contractors conducting remediation activities under the direction of the RPM.
Preventing and mitigating the immediate migration of potential contamination was achieved by conducting two separate operations. The first operation completed was the installation of a three tiered catchment system in the 100-foot section of ditch between the highway and the Yamhill River. Each of the dams consists of a silt fence, several straw bails, and sorbent boom. This will allow water to flow through but will bind up oily residuals.
The second prevention measure required that the integrity of the confining clay layer of the ditch be reestablished in the 4 areas where it was breached and the cobble layer exposed. To do this a bentonite plug and geo-textile cover will be installed. The plugs will be held in place by placing rip-rap in the ditch. (The placement of the rip-rap is part of the original statement of work that is being completed by Gaurdian).
These two prevention operations were conducted in coordination with existing remediation activities and in no way stopped, or slowed other on-site activites. Discussions between EPA OSC Callaghan, EPA’s ER contractors and Remediation contractors (CH2M Hill and Guardian) ensured that this was the case. And that any appropriate aid was offered to Guardian. Guardian indicated that they had other operations that were keeping them busy and that EPA’s ER proposed activities would not hold up their overall operations. Guaridan also did not desire to work as a subcontractor to EPA’s response contractor (ERRS) to ensure these protection strategies were put in place.
START collected grab samples to characterize the contaminants and to delineate the extents of surface contamination in the release area. Analytical Data was submitted on Thursday August 23.
All the bentonite plugs (3) north of HWY 18 have been installed and covered with geotextile fabric. One remaining bentonite layer must be installed by EPA's ER contractor after the area south of HWY 18 (culvert outfall) is excavated by Guardian. The timeline for excavation will be determined by Guardian as it is part of their original SOW. Once it is excavated ERRS contractors will install a confining layer to keep all surface waters away from potential subsurface contamination.
1) Maintain daily communications with ERRS regarding ensure prevention measures (dams) are functioning properly.
2) Review Analytical data package (Week of August 27-30)
3) EPA's removal program will begin to scope out level of effort associated with a potential expanded site investigation.
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