Park 90/5

The Park 90/5 Office Park is approximately 10 acres and is located at 2203 Airport Way South in southern Seattle, Washington. Facilities on the Site include five buildings used or previously used for office and warehouse space, biotechnology laboratories, coffee roasting, a doctor’s office and communications businesses. The areas surrounding the buildings are asphalt-paved parking lots. The City of Seattle acquired the Park 90/5 Site on August 1, 1996. The Seattle Police Department uses some of the property for training, support, and other purposes.
 
The Site was originally part of the tide lands near the mouth of the Duwamish River that were filled near the turn of the century. Between the early 1900’s and early 1980’s, the Site was used for meat packing purposes. Facilities that existed on the Site prior to the mid- 1980’s included stock pens, killing rooms, rendering tanks, sausage factory, smokehouse, lard room, tank shed (containing rendering products such a tallow), saw shed, machine shop, engine and boiler rooms, oil house, steam plant, paint shop, and offices. In the mid- 1980’s the meat packing facilities were demolished except for the former slaughterhouse (Building A). Building A was remodeled in 1985 and the other four buildings (B to E) were constructed between 1985 and 1987.
 
Five underground storage tanks (USTs) have existed on the property. Four of the tanks were associated with the meat packing facilities and were reportedly removed during Site demolition and redevelopment. No tank removal data on the condition of the tanks or tank backfill was found to assess whether leakage had occurred, however oily materials were encountered during geotechnical investigations in 1984 near the reported location of one of the tanks. The fifth UST, a waste oil tank used by a property tenant was removed in 1994 in accordance with Washington State UST regulations.
 
Comparison of soil and groundwater quality data with potential cleanup levels indicates that petroleum hydrocarbons, chromium and arsenic were of potential concern at the Park 90/5 Office Park.
 
A cleanup plan to remediate petroleum containing soils was developed and implemented at three locations (P2, P4, and P5). Remediation consisted of excavating to a practical extent and disposing of soils off-Site that exceeded cleanup levels. Remedial actions were not completed at location P-3 where chromium was detected above cleanup levels. Additional remedial actions are not necessary at this location, in the consultant’s opinion, because of the localized extent of the exceedance, groundwater meets the chromium cleanup level, and because the P-3 area is paved.
Additional excavation in both the sidewalls and bottom was restricted because of geotechnical considerations.
 
Remediation of Site soils had been completed at that time to a practical extent. Available groundwater quality data indicate that groundwater meets cleanup levels except for petroleum hydrocarbons in the immediate vicinity of location P-2, and arsenic. Water quality data from soil probes and wells indicate that petroleum constituents are not migrating from location P-2. No source of arsenic has been discovered at the Site and the arsenic concentrations in groundwater appear to be representative of regional conditions. Because the data, in the opinion of the environmental consultant, indicated little risk to human health and the environment, a “No Further Action” (NFA) was requested from Ecology.  Ecology however, did not agree to the NFA at that time. Ecology wanted additional information and in a March of 1997, Joe Garcia (property owner) received a letter from Ecology that stated that an NFA letter could not be issued because certain issues were not resolved.
 
Summarizing the remaining soil contamination:

• Chromium was measured at a concentration of 990 mg/kg at location P-3. This chromium concentration exceeds the MTCA industrial cleanup level of 500 mg/kg.

• At location P2, residual diesel-range hydrocarbons greater than 2,000 mg/kg remain in soil. At location P4, residual heavy-oil range hydrocarbons of approximately 800 mg/kg remain in soil and at location P-5, residual diesel-range (437 mg/kg) and heavy-oil range (929 mg/kg) hydrocarbons remain in soil. These concentrations exceed the MTCA Method A soil cleanup level of 200 mg/kg.

The available groundwater quality data indicate that the soil chromium concentration at P-3 and the residual petroleum hydrocarbon concentrations at locations P-2, P-4 and P-5 are not leaching and migrating in groundwater at concentrations that exceed cleanup levels.
 
The City of Seattle acquired the Park 90/5 Site on August 1, 1996. An Independent Remedial Action Report (DOF 1996) and a request for a ‘No Further Action’ (NFA) letter were submitted to the Ecology in December 1996. After review of the DOF 1996 report, Ecology requested additional information, including the collection of additional groundwater data (Ecology 1997), that was provided in a report by DOF (1997). In March 1998, Joe Garcia of the City of Seattle received a letter from Ecology (dated March 9) that indicated Ecology would issue an NFA letter for soil contamination from diesel and heavy-oil provided a Restrictive Covenant was recorded with the King County’s auditor’s office. The Restrictive Covenant would note that petroleum hydrocarbon contamination above cleanup levels remained at locations P-2, P-4 and P-5. The Ecology March 9 letter also indicated that the Site would remain on the Confirmed and Suspected Contaminated Sites Report because chromium contamination in soil exceeds the Method C industrial level. The letter indicated that to remove the Site from the list, steps would need to be taken to characterize the nature and extent of chromium at P-3.
 
These issues with chromium and other details were discussed further and ultimately resolved.  Ecology issued an NFA letter June 21, 2001 after a restrictive covenant was recorded with the county.