From 1956 until approximately 1976, Industrial Metal Alloy Company, operated a solder manufacturing company at the Site. Taracorp, Inc., and its predecessor corporations leased the Site to operate a solder manufacturing facility at the Site from 1976 through 1993. NK Holdings, LLC was formed in 2005 and is the corporate successor to Taracorp, Inc.
Slag with high levels of lead have been found in several locations around the IMACO property. Lead contaminated dust was also believed to have escaped through ventilation from the facility while it was in operation. Analytical results indicated that contamination occurs in the surface and subsurface soils above the removal action levels (RAL) for lead and arsenic of 400 ppm and 40 ppm, respectively. The maximum lead concentration detected in surface soils was 113,821 ppm, and the maximum arsenic concentration in surface soils was 430 ppm.
NK Holdings signed a consent agreement with EPA on September 20, 2006 to perform the removal work at the Site. The removal will involve excavation, treatment, and disposal of contaminated soils from the IMACO lot, the Colter Electric property located East of the lot, and three nearby residential yards. EPA will oversee the work done by NK Holdings over the course of this removal action.
During the week of October 8, 2007, Brown & Caldwell mobilized to the site to complete Type II and Type III sampling as defined in the Removal Action Work Plan and the Sampling and Analysis Plan. HEPACO mobilized to the site at this time to begin site preparations including: brush and tree removal from the IMACO lot, equipment removal from the Colter Electric Yard, construction of a silt fence around the cleared areas, construction of a security fence around operational areas, office trailer and decon trailer setup, and utility setup.
On October 15, 2007, HEPACO constructed a combination truck entrance and equipment decontamination pad on the eastern portion of the IMACO lot.
On October 16, 2007, HEPACO hauled tree debris from clearing activities to a mulch and recycling facility.
On October 18, 2007, the EPA OSC and START collected surface soil samples in a pattern based on the Type II and Type III samples collected by Brown & Caldwell the previous week, in order to provide corroborative data for decisions made by Brown & Caldwell’s samples.
- Sampling to determine the aerial and vertical extent of contamination on-site and on adjacent properties (COMPLETE)
- All soils and sediments on-site and on adjacent properties which are contaminated above RALs shall be excavated
- All waste streams shall be disposed of by appropriate measures as determined by the disposal profile
- Restore areas which are disturbed by the removal action to their pre-removal state to the maximum extent practicable
HEPACO temporarily demobilized from the site on October 19, 2007 so that an excavation determination could be made based on sampling results from the previous week. The first load of treatment material is expected to arrive during the week of October 29 and excavation activities will begin shortly afterwards. HEPACO plans to use a 3% by weight mixture of Triple Superphosphate (0-45-0) fertilizer to immobilize lead contamination, in order to dispose of the excavated material as non-hazardous waste. The fertilizer will be mixed with the soil as excavation occurs and then placed into stockpiles on-site. Samples will be collected from the stockpiles and sent for TCLP analysis to determine that the treated soils meet disposal criteria.
KETTLE BOTTOMS
Both work plans suggest the possibility that a recycler may be able to accept the kettle bottoms found on-site (slag waste); and both suggest that the alternative option would be treatment and disposal. The process of crushing and treating this material may require a significant amount of time; so it will be useful to know at an early stage which, if any, facilities may be able to receive the material for recycling. Also, it appears that one or more kettle bottoms have fallen into the stream; eventually, these will need to be removed.
SLAG PIECES
Pieces of slag were found in various locations of the site, ranging from soft ball-sized to marble-sized chunks. Many of the slag pieces were found along the west wall of the IMACO building (grids E9, F9, G9, H9, and I9) and some slag material appears to have been unearthed by the trenching machine when the silt fence was installed. Also, some small slag pieces were found at the bottom of a small slope on grids N4, N5, N6, O4, O5, and O6. In the event that results of Type II and Type III sampling determine that excavation is unnecessary in a grid location where slag pieces can be found on the surface, then it will (at least) be necessary to remove the slag material from the grid's surface as visual contamination.
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