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DEQ SITE ASSESSMENT PROGRAM - STRATEGY RECOMMENDATION Site Name: Hoffman Construction Co. site CERCLIS Number: none DEQ ECSI Number: 1522 Site Address: 8027 NE Killingsworth St. Portland, OR 97218 Recommendation By: Gil Wistar, Voluntary Cleanup and site Assessment Section, DEQ Northwest Region Approved By: Michael E. Rosen, Manager, Voluntary Cleanup and Site Assessment Section, DEQ Northwest Region Date: April 12, 1994 Background: Not much is known about Hoffman Construction Co. (Hoffman), except that the site is active and has been in operation since at least 1973. Hoffman uses the site to store, maintain, and repair equipment employed in its commercial and industrial construction business. In late 1988, Hoffman decided to· remove its four underground storage tanks, under contract to Pegasus Waste Management, Inc. These four tanks contained gasoline, diesel, kerosene, and waste oil, respectively. Pegasus removed the four tanks in January 1989, and none except the 8,000-gallon waste oil tank appeared to have caused significant contamination. Although the waste oil tank showed no evidence of holes or leakage, there was obvious soil contamination in the pit, which was attributed to overfilling or surface spillage. A sample of oil from the tank contained 1,320 ppm 1,1,1-trichloroethane (TCA) and 1,200 ppm PCB, so DEQ apparently required disposal of the tank at a Class I landfill, and disposal of contaminated soil from around the tank at an "acceptable" facility. (This information is taken from the Pegasus report; there is no file documentation of such DEQ directives.) Upon discovery of contaminated soil in the pit, Pegasus submitted a sample of the soil for analysis. According to the 1/18/89 lab report, this sample contained 6 ppm PCB (Aroclor 1248), as well as methylene chloride, TCE, and perchloroethylene (PCE). (This lab report used EPA Method 450.1 (total organic halogens) to derive these results, and found 67.9 ppm organic halogens; the quantities of methylene chloride, TCE, and PCE were not specified.) Based on 1 these results, Pegasus prepared a detailed sampling and investigation plan, which focused on PCBs. It is unknown whether this plan was implemented; there are no records in the file to suggest that it was carried out. In February 1989, Spencer Environmental Services collected an additional soil sample from the bottom of the tank pit, and an additional sample of the waste oil itself. The soil sample, taken from an area of discoloration, contained 2,025 ppm total halogens, 22 ppm Aroclor 1248, and 28,665 ppm oil-range hydrocarbons. The waste oil sample contained 2,274 ppm total halogens, 85 ppm Aroclor 1~48, and 310 ppm total lead. After excavating more soil from the pit, to a depth. of about 20 feet, a bottom sample contained 346 ppm total halogens, 0.37 ppm Aroclor 1254 (not 1248), and 270 ppm oil. In March 1989, Spencer installed two test borings near the tank pit to obtain more information on the extent of contamination. Test hole 1 was located 1.5 feet from the northeast corner of the pit, and test hole 2, 16 feet north of the pit. Analytical results are shown l:>elow. CONSTITUENT !EPA Method 9020) TEST HOLE 1, 20 ft. TEST HOLE 1, 25ft. TEST HOLE2, 20ft. TEST HOLE2, 25ft. TEST HOLE2, 30ft. Total halogens, ppm 167.5 157 223 1,701 271 Organic halogens, ppm 115 107 208 1,686* 255** Inorganic halogens, ppm 52.5 50 15 15 16 * ** Identified by lab report as 1,1,1-trichloroethane (TCA). Identified by lab report as chloroform. In the meantime, about 45 yards.of contaminated soil from the pit were stockpiled on site, and Hoffman Construction applied through Metro to dispose of the soil at st. John's Landfill in North Portland. After consulting with DEQ, Metro requested additional profiling on the soil as a condition of accepting the application. Then, in July 1989, Metro .denied the application, after learning that Hoffman had already returned the soil to the pit and filled the hole to grade. DEQ's Leaking Underground Storage Tank (LUST) section closed site file #26-89-005 on July 10, 1989, indicating in its closure letter to Hoffman that no further action was needed with respect to the former gasoline, diesel, and kerosene tanks. LUST had previously referred the waste oil tank contamination to DEQ's Environmental Cleanup Division (ECD), and indicated in the letter that the 2 situation warranted further action, under ECD oversight. It appears that ECD was consulted about the site, but did not take an active role in follow-up. In a March 28, 1989 E-mail to Loren Garner of LUST, Paul Burnet of ECD made the following points: 1) If the source of the halogens were a pre-1973 spill (the facility had indicated that it had not used chlorinated solvents since 1973), extensive offsite migration may have occurred, and high soil levels at depth were "not a good sign." 2) Chlorinated solvents like TCE typically will not leave much of a trace as they pass through soil, indicating that much higher concentrations of halogens might be found at greater ·depths or further downgradient. 3) The water table had not been located, so that it was not known whether groundwater had been affected. 4) TCE levels in soil were orders of magnitude above the federal drinking water.standard of 5 ~gfL. Despite these concerns, the only evidence of ECD action at the site is a June 27, 1989 letter to Cecil Drinkward, President of Hoffman Construction, in which ECD recommends that Hoffman initiate site cleanup. Site Assessment considers groundwater to be the most threatened exposure pathway at this site. This is because the depth of documented contamination makes the other three pathways unlikely to be affected. In addition, the site is located at the western edge of the Portland Water Bureau (PWB's) Columbia South Shore Planning Area (see attached map), where most of the city's backup drinking water wells are located. Although PWB is not currently drawing water from these wells, it is likely that they will be needed in the near future due to population growth and the unpredictability of surface water supplies. Specifically, the Hoffman site is 1.5 miles west of the nearest PWB production well, #29, which is screened in deep Troutdale aquifers. The site is also located 1.5 miles northwest of Parkrose #1, a backup well now owned by PWB that is screened in shallower, unconfined water-bearing zones. In addition, Bible Temple School maintains an active drinking water well between 1 and 1.25 miles southeast of the site;. it serves up to 2, 400 persons (Sunday worship). The depth of this well is unknown, as is the direction of local groundwater flow. References: site Assessment has reviewed the following sources in preparation of the background information above: A copy of a report entitled Underground 3 Fuel Storage. Tank Removals and Site Remediation Final Report, Pegasus Waste Management, Inc. (undated). prepared by An application to dispose of special wastes, filed at Metro, which includes lab results from an investigation conducted by Spencer Environmental Services. Notes and correspondence from the LUST file. Significant concentrations of chlorinated hydrocarbons have been documented in soil below depths of 25 feet at this site. With respect to soil, this contamination may extend to much greater depths and may have migrated off-site. Groundwater may also be contaminated, particularly in light of Hoffman's having apparently backfilled the former waste oil pit with contaminated excavation spoils in 1989. Due to the site's location on the edge of the Columbia South Shore Wellfield area, the types and concentrations of contaminants found, and the unknown extent of chlorinated hydrocarbons, Site Assessment recommends further action at the Hoffman site, under high priority. The owner/operator should characterize soils on-site (and off-site as necessary) with respect to types and extent of PCBs and chlorinated solvents. At the same time, a groundwater investigation should be conducted to determine impacts to groundwater and to assess the potential damage to local drinking water supplies .. Recommendation/Action: In addition, this site should be added to the Confirmed Release List and Confirmed Release Inventory. Referrals Within or outside DEQ: This site has not been referred to another division of DEQ or to an outside regulatory agency. DEQ's LUST section referred the site to DEQ' s Environmental Cleanup Division in 1989. Other: This site is currently listed on DEQ's ECSI database; it will be updated with information contained in this decision document, and to reflect Site Assessment's decision for further action at the site. 4 '\-tOffA~N coNS<f'f'-VC\ION COLUMBIA SOUTH SHORE LEGEND COLUMBIA SOUTH SHORE BOUNDARY BLA 'I SGA + ~ TSA )I( CRSA+ SCALE 1000 0 1000 2000 3000 FEET i - ---~'"" --~-----~·- . --·-~--~------ SITE PRIORITIZATION WORKSHEET Site Name: ·~ c~ Co., Medium of Concern: ~ H M L NA 1. Substance Characteristics: A. Toxicity/Persistence: B. Mobility: X X .X 2. Contamination Route: 3. Vulnerable Targets: .. A. Population Affected~ X - X B. Sensitive Environments/Species: 4. Verification of Release/Threatened Release: 5. Quantity/Concentration of Substance: 6. Environmental Effects on Release Control: Overall Site Priority: X X. X X Comments: Evaluator: __ ~~~~-~~----~---·--~--~----~----------- Date: ~ NOTE: Under no circumstances can a documented release above action levels be NFA'd without additional assessment and/or sufficient supporting documentation.