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Environmental Cleanup Site Information (ECSI) Database Site Summary Full Report - Details for Site ID 5694, 4th Main

This report shows data entered as of April 26, 2018 at 6:21:42 AM

This report contains site details, organized into the following sections: 1) Site Photos (appears only if the site has photos); 2) General Site Information; 3) Site Characteristics; 4) Substance Contamination Information; 5) Investigative, Remedial and Administrative Actions; and 6) Site Environmental Controls (i.e., institutional or engineering controls; appears only if DEQ has applied one or more such controls to the site). A key to certain acronyms and terms used in the report appears at the bottom of the page.

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Site Photos

Click to View Photo Picture Date Caption Size
View Photo 01/06/2014 New building nearing completion. 7995 Kb
View Photo 08/29/2012 Leaking heating oil tank found below the former post office building. Dark soil is likely contaminated. 801 Kb

General Site Information

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: No further action required
  Brownfield Site: Yes NPL Site: No Orphan Site: No Study Area: No
Property: Twnshp/Range/Sect: 1N , 2W , 31 Tax Lots: 5200
  Latitude: 45.5225 deg. Longitude: -122.985 deg.  Site Size: 1.11 acre
Other Site Names:

Site Characteristics

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.
Site History: 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.
Environmental/Health Threats:
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.

(RKW 2/14) Staff Report prepared. Interested parties to be given two weeks to comment on Staff Report before the NFA is issued. A public comment period runs through March 2014 for the Certificate of Completion of the Consent Order/PPA for redevelopment of the property by Tokola Properties.
Data Sources:

Substance Contamination Information

Substance Media Contaminated Concentration Level Date Recorded
BENZENE Groundwater 0.43 ug/L 9/29/2011
BENZO(a)PYRENE Soil 0.076 mg/kg 9/29/2011
DIESEL - FUEL OIL Soil 4,280 mg/kg 10/28/2011
LEAD Soil 268 mg/kg 10/28/2011
OIL OR FUEL RELATED COMPOUNDS Soil 1,170 mg/kg 10/28/2011

Investigative, Remedial and Administrative Actions

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 08/15/2012 Robert Williams VCS
Prospective Purchaser Agreement 04/04/2012 07/06/2012 Robert Williams VCS
REMEDIAL ACTION 08/15/2012 11/15/2012 Robert Williams VCS
NO FURTHER STATE ACTION REQUIRED  (Primary Action) 04/01/2014 04/01/2014 Robert Williams VCS
Certification of Completion 04/21/2014 04/21/2014 Cheyenne Chapman VCP

Key to Certain Acronyms and Terms in this Report:

For more information on this site contact the Northwest regional office.