|DEQ Home > Land Quality > Environmental Cleanup > ECSI > Site Summary Full Report|
Environmental Cleanup Site Information (ECSI) Database
|Click to View Photo||Picture Date||Caption||Size|
|View Photo||08/29/2012||Leaking heating oil tank found below the former post office building. Dark soil is likely contaminated.||801 Kb|
|Site ID: 5694||Site Name: 4th Main||CERCLIS No:|
|Address:||350 E Main St. Hillsboro 97123|
|County: Washington||Region: Northwest|
|Other location information:|
|Investigation Status:||Suspect site requiring further investigation|
|Brownfield Site: Yes||NPL Site: No||Orphan Site: No||Study Area: No|
|Property:||Twnshp/Range/Sect: 1N , 2W , 31||Tax Lots: 5200|
||Site Size: 1.11 acre|
|Other Site Names:|
|General Site Description:||
As of February 2012, the property is developed with a two-story, approximately 5,000-square-foot commercial building that is unoccupied and used for storage. The structure was built in 1954 as a bank branch office. A partial utility basement area underlies the southern fifth of the structure. A below-grade sump is located along the east wall of the basement, which is likely used for water intrusion control with a sump pump. Attached to the eastern exterior of the structure is a canopy and drive-through teller area
that was constructed in the 1970s. The remainder of the property is covered with an asphalt-paved parking lot and some landscaping.
From the late 1880s through the late 1950s, the subject property was used for mixed residential and commercial purposes. By 1892, it was developed with a residence in the NE portion and a small washhouse or laundry in the north-central area. Three additional residences were present by 1912, located at the east-central, SE and NW portions of the property, and the former washhouse had been replaced with a livery and feed store, which remained onsite through 1936. By 1936, the original (NE) residence was no longer present, and a U.S. Post Office had been constructed in its place. By 1940, the livery/feed store and NW residence had been removed, and an automotive fuel station was present at this area. The fuel station remained onsite through at least 1951.
All of the remaining residences and outbuildings were removed in approximately the early 1950s, and the existing building was constructed in 1954 for use as a branch bank. The U.S. Post Office that was formerly present at the NE portion of the property was removed at some time between 1972 and 1979, at which time the existing drive-through teller window and canopy were constructed at the E side of the bank building. The building was used as a bank from its construction in 1954 until it was vacated in approximately 1998. Since 1998, the building has been used for storage.
|Contamination Information:||[Excerpt from Jan. 2012 Phase II ESA from Hahn & Associates]: In summary, the four zones of soil contamination discovered at the site encompass a rather large volume of approximately 2,500 cubic yards, of which 500 cubic yards (in the SW Area) may contain chemical concentrations [i.e. for oil and/or benzo(a)pyrene] that would exceed risk criteria for Urban Residential uses of the site. The areas of soil contamination appear to be adequately characterized and delineated. Although the extent of soil contamination potentially present off-site beneath the adjacent SE 4th Avenue right-of-way at the Post Office Area has not been directly determined, its extent to the east is inferred to be limited.|
|Manner and Time of Release:||Releases of petroleum at the site appear to be historical and largely related to heating oil tanks. Surface contamination may be related to oiling gravel surfaces for dust control. There is little evidence of contamination from the past gas station at the site.|
|Hazardous Substances/Waste Types:||petroleum hydrocarbons and related chemicals|
|Pathways:||Direct contact or excavation worker contact and potential vapor intrusion.|
|Status of Investigative or Remedial Action:||
A Remdial Action Work Plan was approved by DEQ in early July 2012. The planned development for the site includes underground parking for future building tenants and much of the footprint of the site will require excavation up to 14 feet in depth. This pre-construction excavation will also accomplish site cleanup. Contaminated soil will be segregated from clean soil and trucked to the nearby Hillsboro Landfill for disposal. There is some potential for contamination to extend offsite into the 4th Avenue right-of-way in the NE corner of the property; this will be evaluated during excavation. Excavation to proposed depths will likely generate groundwater in the pit such that dewatering will be required. Since the groundwater has minor contamination it will be contained for possible treatment before disposal. Excavation is scheduled for late July 2012.
(RKW 8/12) Excavation began in late August and a leaking heating oil tank was soon found below the former post office building. The tank was removed for proper cleaning and disposal. The soil contaminated by the tank will be removed as part of the excavation process and confirmation samples will be collected after excavation is complete.
|Substance||Media Contaminated||Concentration Level||Date Recorded|
|DIESEL - FUEL OIL||Soil||4,280 mg/kg||10/28/2011|
|OIL OR FUEL RELATED COMPOUNDS||Soil||1,170 mg/kg||10/28/2011|
|Action||Start Date||Compl. Date||Resp. Staff||Lead Pgm|
|Site added to database||02/22/2012||02/22/2012||Gerald Gamolo|
|SITE INVESTIGATION||02/22/2012||Robert Williams||VCS|
|Prospective Purchaser Agreement||04/04/2012||07/12/2012||Robert Williams||VCS|
|REMOVAL (Primary Action)||08/15/2012||11/15/2012||Robert Williams||VCS|
Key to Certain Acronyms and Terms in this Report:
You may be able to obtain more information about this site by contacting Robert Williams at the Northwest regional office or via email at firstname.lastname@example.org. If this does not work, you may contact Gil Wistar at (503) 229-5512, or via email at email@example.com or contact the Northwest regional office.
For more information about ECSI call Gil Wistar at 503-229-5512 or email.
For more information about DEQ's Land Quality programs, visit the DEQ contact page.