From: Soren Hill

Sent: Tue Jan 16 13:52:29 2024

To: PUGH Mark * DEQ

Cc: Andie Fitzgerald; Chuck Esler; Tanya Battye

Subject: RE: Former 5 Star Cleaners - Q4 Progress Report

Importance: Normal

Attachments: image001.jpg; 10_October 2023 O& M Field Report.pdf; 11_November 2023 O& M Field Report.pdf; 12_December 2023 O& M Field Report.pdf; 20231012 Monthly O& M Field Notes.pdf; 20231116 Monthly O& M Field Notes.pdf; 20231213 Monthly O& M Field Notes.pdf; ALS Labs_2330303-Report.pdf; Pace Labs_L1666709-Report.pdf;

Hi Mark,

Attached are the unzipped files. Please confirm receipt. Thank you!

From: PUGH Mark * DEQ <mark.pugh@deq.oregon.gov>

Sent: Tuesday, January 16, 2024 1:21 PM

To: Soren Hill <shill@farallonconsulting.com>

Cc: Andie Fitzgerald <afitzgerald@terwilligerplaza.com>; Chuck Esler <cesler@farallonconsulting.com>; Tanya Battye <tbattye@farallonconsulting.com>

Subject: RE: Former 5 Star Cleaners - Q4 Progress Report

Soren, I am unable to open the field or analytical report files.

From: Soren Hill <shill@farallonconsulting.com>

Sent: Monday, January 15, 2024 3:51 PM

To: PUGH Mark * DEQ <mark.pugh@deq.oregon.gov>

Cc: Andie Fitzgerald <afitzgerald@terwilligerplaza.com>; Chuck Esler <cesler@farallonconsulting.com>; Tanya Battye <tbattye@farallonconsulting.com>

Subject: Former 5 Star Cleaners - Q4 Progress Report

Mark,

This email provides a quarterly progress report for the former Five Star Cleaners property at 2305 SW 6th Avenue (DEQ ECSI Site ID No. 6276). This progress report is being submitted for the fourth quarter of 2023, on behalf of Pacific Skyline Holdings II, LLC.

Actions taken during the previous 3 months:

• * Monthly O&M visits by Farallon were conducted on October 12, November 16, and December 13, 2023. The vapor recovery wells and collection pits operated continuously during this time. Monthly O&M field reports are attached. Monthly O&M activities included monitoring the following parameters:

o Concentrations of volatile organic compounds (VOCs) were measured using a hand-held photoionization detector (PID) at select monitoring points including at the vapor collection system, sub-slab vapor pins, and vapor recovery wells. PID readings are summarized in Table 1 (attached).

o Differential pressures were measured at the subslab vapor points (VP-5 through VP-8) using a hand-held vacuum gauge. Differential pressure readings are summarized in the O&M field reports.

· Semi-annual air samples were collected from the influent (pre-carbon) and effluent (post-carbon) lines of the vapor granular activated carbon treatment vessels using summa canisters on October 12, 2023. The samples were submitted to Pace Analytical laboratories for analysis using U.S. Environmental Protection Agency (EPA) Method TO-15 for VOCs including but not limited to tetrachloroethene (PCE) and trichloroethene (TCE). Analytical results for the vapor collection system are shown in Table 2 (attached). The analytical report is also attached.

· Indoor and outdoor ambient air samples were collected using Radiello badges between October 12 and October 26, 2023. The samples were submitted to ALS Laboratories for analysis for PCE and TCE by EPA Method TO-17. Ambient air analytical results are shown in Table 3 (Attached). The analytical report is also attached.

· The Vapor Collection System Operations and Maintenance (O&M) Manual was revised with updated contact information, minor text edits providing clarity to field staff, and a redundant system checklist was added to the monthly inspection form. The revised O&M Manual (revised October 20, 2023) was submitted to DEQ via email on October 25, 2023.

Summary of sampling, test results, and any other data generated or received during the previous 3 months:

Monthly O&M field reports are attached. PID readings are tabulated in Table 1 (attached).

• * PID readings from vapor collection system exhaust were as follows:
  • * VOCs were detected in the Pits Exhaust from the vapor collection pits at the following levels: 0.6 parts per million (ppm) in October 2023, 0.1 ppm in November 2023 and were not detected in December 2023.
  • * VOCs were detected in the Pre-Carbon Effluent from the vapor recovery wells at the following levels: 8.1 ppm in October 2023, 9.2 ppm in November 2023, and 13.4 ppm in December 2023.
  • * VOCs were not detected in the Post-Carbon Effluent from the vapor recovery wells in October, November, or December 2023.
• * Positive pressure was measured at the exhaust stack for the vapor pits collection system in October, November, and December 2023, indicating the system is functional.
• * A vacuum was observed at the carbon inlet for the recovery wells in October, November, and December 2023, indicating the system is functional.
• * A pressure differential ranging from -0.004 to -0.046 inches of water column was measured at vapor points VP-5 through VP-7 during October, November, and December 2023 monitoring, except November 2023 when no pressure differential was measured at VP-5. No pressure differential was measured at VP-8 during October, November, and December 2023 monitoring.
  • * Readings from the fourth quarter’s O&M indicate that the system is functional. However, Farallon is investigating a replacement fan for the system due to the absence of measurable vacuum at VP-8.

Pre- and post-carbon and indoor and outdoor air sampling analytical results from the October 2023 sampling event are presented in Tables 2 and 3, respectively. Those results are summarized as follows:

• * The carbon treatment of extracted vapors is operating as intended. The laboratory report is provided as an attachment. Relevant results are noted below:
  • * 99.97% removal of tetrachloroethene (26,500 ug/m3 pre-carbon to 8.49 ug/m3 post-carbon).
  • * Removal of trichloroethene, cis-1,2-dichloroethene, and trans-1,2-dichloroethene post-carbon to concentrations less than laboratory reporting limits.
• * Analytical results for indoor ambient air samples collected between October 12 and October 26, 2023, indicated PCE concentrations were below applicable Risk Based Concentrations (RBCs) for Air Inhalation (Occupational, Residential, and/or Urban Residential) and ranged from 1.7 to 4.4 ug/m3. The outdoor location sample result was below the RBCs at 0.25 ug/m3. TCE concentrations were below RBCs and less than the laboratory reporting limits at all sample locations. The laboratory report is provided as an attachment.

A description of any problems experienced during the previous three months and actions taken to resolve them:

• * The vacuum collection pit piping was checked for the accumulation of water during the October and December O&M events. No water was observed during the October O&M event. Approximately 1 liter of accumulated water was removed from the subsurface piping system using a peristaltic pump during the December O&M event.
• * Analytical results for ethylbenzene, toluene, and xylenes concentrations increased in both the pre- and post-carbon air samples, but concentrations remained under action levels.

Actions scheduled in the next 3 months:

• * Monthly O&M visits will be conducted in January, February, and March 2024.
• * Semi-annual vapor sampling and indoor air sampling will be conducted in February 2024 (see O&M plan for sampling details).
• * In the event heavy rainfall occurs in the upcoming months, the piping system will be checked for water accumulation.
• * Radon fan replacement will be evaluated based on sub-slab pressure differential data collected to date.

If DEQ has questions about the information provided in this progress report, please do not hesitate to contact us.

Thank you,