The date, site name, report author, report recipient, and report number are presented above.

Engineering Management Support, Inc. Memorandum To: Jesse Aviles, EPA RPM, VB/I70 Superfund Site From: Timothy C. Shangraw Date: October 17, 2017 Re: POLREP #27 - Vasquez Boulevard/Interstate 70 (VB/I70) Superfund Site, Operable Unit 2, Removal Action ======================================================================= On behalf of the City and County of Denver (Respondent), Engineering Management Support, Inc. (EMSI) is submitting this Pollution Report (POLREP #27) in accordance with Section 4.c of Appendix C to the Administrative Settlement Agreement and Order on Consent for Removal Action, for the subject Superfund Site (the Site). This report follows the outline detailed in Section 4.c of Appendix C, and contains pertinent new information specified in the Superfund Removal Procedures, Removal Response Reporting: POLREP and On-Scene Coordinator (OSC) Reports (EPA, 1994). Section I Heading The date, site name, report author, report recipient, and report number are presented above. Section II Response Information This reporting period extended from September 1 through 30, 2017 during which time, the following activities occurred: Excavation of Regulated Asbestos-Contaminated Soils (RACS) and hauling to and disposing at the Denver Arapahoe Disposal Site (DADS); Excavation of non-regulated Asbestos-Contaminated Soils (non-racs) and stockpiling it for future use onsite or hauling to and disposing at DADS; Construction of the concrete box conduit, outlet wing walls, and open channel sidewall footings through the Coliseum Parking Lot (CPL); Pumping and treatment of groundwater from dewatering zones 1, 2, 3a, and 3b; Construction of the drop inlet structure and reinforced box conduits (RBCs) in dewatering zone 2 (beneath Delgany sanitary sewers); Construction of the lateral drain box in dewatering zone 3a; and On-site and off-site monitoring for air quality, dust, and odors. The volumes of RACS and non-racs excavated and managed, and the volumes of water pumped, treated, and returned to the South Platte River, are summarized in Table 1. On-site monitoring for volatile organic compounds (including methane), odor, and visible dust

Memorandum POLREP #27 VB/I70, OU2 removal Action October 17, 2017 Page 2 emissions occurred continuously during excavation and drilling activities. In addition, monitoring for airborne asbestos fibers proceeded in accordance with Section 5.5 of the Colorado Department of Public Health and Environment (CDPHE) Solid Waste Regulations. Due to their overall size, daily monitoring reports for volatile organic compounds, odor, dust, and asbestos are being submitted under separate cover. Off-Site monitoring by Denver for PM 10, airborne lead and arsenic at four locations within the monitoring boundary continued throughout the reporting period. Sampling from these stations occurred every sixth day throughout the month. Results were all below Occupational Safety and Health Administration 8-hour limits and National Ambient Air Quality Standards. Monthly monitoring report are posted on the Globeville Landing Outfall (GLO) project web site at: https://www.denvergov.org/content/denvergov/en/environmental-health/environmentalquality/land-use-and-planning.html. As part of the GLO project s Community Outreach program, a community hotline was operated. No complaints were received during the reporting period. The Community Advisory Group (CAG) held its seventh and eighth meetings on September 12 th and October 10 th, respectively. Meeting minutes are posted on the VB/I-70 Superfund Community Advisory Group web site. The next CAG meeting is scheduled for November 14 th. The following project meetings were held in September: Weekly GLO Project Status Meetings (September 7, 14, 21, and 28, 2017); and EPA monthly progress meeting (September 20, 2017). Lastly, a 3-week look-ahead Construction Schedule is attached to this POLREP. Section III Issues, Resolutions, and Planned Activities A Quality Assurance Audit was performed on Asbestos-Containing Soils Daily Reports (ACSRs) prepared by Kleinfelder during the month of August for consistency with Section 5.5 of Colorado s Solid Waste Regulations (CSWRs) and the Final Materials Management Plan (MMP) (EMSI, 2016). No deficiencies were noted. A copy of this Audit Report is attached to this POLREP. Monitoring of treated effluent from the GLO project continued during the reporting period in accordance with Discharge Permit Number CO0049002. All monitored parameters met discharge limits. The U.S.EPA and the Respondent have exchanged correspondence in agreement of updating the Remedial Investigation and Feasibility Study for the VB/I-70 Operable Unit 2 site. The agreement correspondence letters are attached to this report.

Memorandum POLREP #27 VB/I70, OU2 removal Action October 17, 2017 Page 3 Planned activities for the next reporting period consist of: Continued construction of the concrete box conduit, outlet wing walls, and open channel sidewall footings through the CPL; Grading and preparation of subgrade material for installation of the strengthening layer in the CPL; Continued installation of the inlet drop structure and RBC conduits in the GLP; Continued construction of lateral drain boxes in dewatering zone 3a; Continued dewatering in zones 1, 2, 3a and 3b; and Continued on-site and off-site monitoring of air quality. To maintain effective and transparent communication during GLO implementation, EPA and CDPHE personnel are invited to participate in weekly coordination meetings at Kiewit s RiNo office. The next EPA Monthly Status meeting will be held on October 18 th at 9:00 in the Webb building. Please call Jennifer Luthi (720.865.5432) or me (303.619.5179) if you have any questions. Attachments: September 2017 Summary of GLO Construction Activities 3-Week Look-Ahead Schedule QA Audit Report #5

Table 1: Summary Construction Report for September 2017 Current Month QTY QTY to date Comments EXCAVATION/HAULING # of days Excavation occurred Globeville park 6 76 # of days Excavation occurred Municipal Landfill 31 Volume of Racs Excavated (CY) 5,950 75,359 From Globeville Park and Coliseum Parking lot Volume of Racs hauled to DADS (CY) 5,950 75,359 From Globeville Park and Coliseum Parking lot Volume of Non-Racs Excavated (CY) 58,577 Volume of Non-Racs stockpiled onsite (CY) 12,606 Claystone from drop inlet stockpiled for reuse Volume of Non-Racs hauled to DADS (CY) 45,971 Volume Hauled to Clean Harbors (CY) 0 GROUT AND STONE COLUMNS number of grout columns installed this month 0 1,091 All Stone and Grout columns are complete Grout column SPT testing results 0 0 All Stone and Grout columns are complete number of stone columns installed per month 0 575 All Stone and Grout columns are complete stone column test results 0 0 All Stone and Grout columns are complete REMEDIATION DEWATERING AND TREATMENT LF of underdrain/wick wells installed 600 Volume of water transported and treated at MFEI 2,436,900 20,180,375 Volume of treated water, including dilution, discharged to S. Platte 2,359,468 20,596,404 Analytical results 0 AUGUST DMR submitted CONSTRUCITION DEWATERING status of permit compliance LINER INSTALLATION % complete during the month N/A QC/QA testing results N/A Issues and Resolutions N/A MODCP RESULTS Daily Methane, Odor, and Dust monitoring reports Issues and Resolutions COMMUNITY OUTREACH Summary of Calls to hotline Issues and Resolutions

Globeville Phase 1A Schedule Title Current Week Phase 1A 3 week schedule Monday, October 02, 2017 Item Activity Description Work performed by Start Finish Shift Current Forecast Forecast Forecast Comments 10/02 10/02 10/03 10/03 10/04 10/04 10/05 10/05 10/06 10/06 10/07 10/07 10/08 10/08 10/09 10/09 10/10 10/10 10/11 10/11 10/12 10/12 10/13 10/13 10/14 10/14 10/15 10/15 10/16 10/16 10/17 10/17 10/18 10/18 10/19 10/19 10/20 10/20 10/21 10/21 10/22 10/22 10/23 10/23 10/24 10/24 10/25 10/25 10/26 10/26 10/27 10/27 10/28 10/28 10/29 10/29 M T W T F Sa Su M T W T F Sa Su M T W T F Sa Su M T W T F Sa Su 1 2 EARTHWORK (Excavation) 3 Over-Exc RACS Landscape Area Outfall ESA 09/25/17 10/05/17 day 4 Haul off RACS South of Arkins ESA 10/12/17 10/13/17 day 5 Channel Exc in Globeville Park (plug) ESA 10/06/17 10/11/17 day 6 Over-Exc Northside of landfill ESA 10/16/17 10/18/17 day 7 Locate/clean Stone columns Ames 10/09/17 10/27/17 day Install UV piping under N. Lateral Drain Box Ames 8 EARTHWORK (Backfill) 9 Rubblize Coliseum Parking lot (Southside) Ames 10/17/17 10/18/17 day 10 Place Fill (phase 2) coliseum parking lot Ames 10/04/17 10/11/17 day Place Fill (import) coliseum parking lot Ames 10/11/17 10/20/17 day 11 Backfill Coliseum conduit and Transition # 1 Ames 09/25/17 10/13/17 day 12 Embankment Transtion # 1 (phase 1 stockpile) Ames 10/05/17 10/13/17 day 13 14 DROP INLET 15 F/R/P Deck With orific plates Ames 10/12/17 10/27/17 day 16 17 DROP OUTLET 18 Excavate Drop Outlet CIP and Wing walls Ames 10/07/17 10/09/17 day 19 F/R/P Drop Outlet Wing wall Footings Ames 10/09/17 10/20/17 day 20 F/R/P Drop outlet CIP Box floor Ames 10/23/17 10/27/17 day 21 22 23 S. LATERAL DRAIN BOX 24 F/R/P S. lateral Wall pour # 3 Ames 09/24/17 10/04/17 day 25 F/R/P S. lateral wall pour # 5 Ames 09/24/17 10/04/17 day 26 F/R/P S. lateral wall pour # 4 Ames 10/05/17 10/13/17 day 27 F/R/P S. lateral wall pour # 6 Ames 10/05/17 10/13/17 day 28 29 30 EAST PARK WALL 31 F/R/P East park Wall Footing Section 4 Ames 09/27/17 10/06/17 day 32 F/R/P East park Wall Footing Section 5 Ames 09/29/17 10/11/17 day 33 F/R/P East park Wall Footing Section 6 Ames 10/02/17 10/06/17 day 34 F/R/P East Park wall section 4 Ames 10/06/17 10/12/17 day 35 F/R/P East Park wall section 6 Ames 10/06/17 10/12/17 day 36 F/R/P East Park wall section 5 Ames 10/13/17 10/19/17 day 37 38 39 COLISEUM CONDUIT OUTLET

Engineering Management Support, Inc. QA Audit Report #5 To: From: cc: Matt Ceresa, Kiewit, Tim Shangraw, EMSI Jennifer Luthi, DEH; Steve Gonzales, DEH; Bret Banwart (DPW); Brian McLaren (DPW); and Patrick Riley (DPW) Date: October 9, 2017 Re: Audit of Kleinfelder CABI Notes, August 2017, Globeville Landing Outfall Project Representatives from Engineering Management Support, Inc. (EMSI) reviewed Asbestos- Containing Soils Daily Reports (ACSRs) prepared by Kleinfelder during the month of August 2017 for consistency with Section 5.5 of Colorado s Solid Waste Regulations (CSWRs) and the Final Materials Management Plan (MMP) (EMSI, 2016). Documentation of the review is presented in the attached summary table. AUDIT FINDINGS Quality Control continues to be implemented well. As shown in the attached table, all audited parameters complied with Section 5.5 of the CSWRs and the MMP. ACTION REQUIRED No corrective action is required. Denver and EMSI will continue to monitor Ames/Kleinfelder s implementation of agreed-to reporting procedures and identify any area(s) in need of improvement during weekly progress meetings and if necessary, in subsequent QA Audit Reports. Page 1

Aug 1st-Aug31st QA of CABI daily logs per Colorado Regulation 5.5.7 L (Documentation) and Final Materials Management Plan Page 1 1C 1A 1B 1D Personnel Date Grid Grid Site Description Description Description of Description Description Friability per CABI diagram description of site of equipment hand removals of types of suspect of ACMs Notes agree w including activities use including of debris materials discussed CABI location locations Lanaia Carveth 8/1/17 yes yes yes yes yes yes yes yes yes Tyler Godby 8/1/17 yes yes yes yes yes yes yes yes yes Tyler Godby 8/2/17 yes yes yes yes yes yes yes yes yes Mitchell Reese 8/2/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/3/17 yes yes yes yes yes yes yes yes yes Tyler Godby 8/3/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/4/17 yes yes yes yes yes yes yes yes yes Tyler Godby 8/4/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/5/17 yes yes yes yes yes yes yes yes yes Tyler Godby 8/7/17 yes yes yes yes yes yes yes yes yes Tyler Godby 8/8/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/8/17 yes yes yes yes yes yes yes yes yes Tyler Godby 8/9/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/9/17 yes yes yes yes yes yes yes yes yes Tyler Godby 8/10/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/10/17 yes yes yes yes yes yes yes yes yes Tyler Godby 8/11/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/11/17 yes yes yes yes yes yes yes yes yes Tyler Godby 8/12/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/14/17 yes yes yes yes yes yes yes yes yes Billy Godby 8/14/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/15/17 yes yes yes yes yes yes yes yes yes Billy Godby 8/15/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/16/17 yes yes yes yes yes yes yes yes yes Tyler Godby 8/16/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/17/17 yes yes yes yes yes yes yes yes yes Tyler Godby 8/17/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/18/17 yes yes yes yes yes yes yes yes yes Tyler Godby 8/18/17 yes yes yes yes yes yes yes yes yes Tyler Godby 8/19/17 yes yes yes yes yes yes yes yes yes

1C 1A 1B 1D Personnel Date Grid Grid Site Description Description Description of Description Description Friability per CABI diagram description of site of equipment hand removals of types of suspect of ACMs Notes agree w including activities use including of debris materials discussed CABI location locations Lanaia Carveth 8/21/17 yes yes yes yes yes yes yes yes yes Tyler Godby 8/21/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/22/17 yes yes yes yes yes yes yes yes yes Billy Godby 8/22/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/23/17 yes yes yes yes yes yes yes yes yes Tyler Godby 8/23/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/24/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/25/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/26/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/28/17 yes yes yes yes yes yes yes yes yes Tyler Godby 8/28/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/29/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/30/17 yes yes yes yes yes yes yes yes yes Tyler Godby 8/30/17 yes yes yes yes yes yes yes yes yes Lanaia Carveth 8/31/17 yes yes yes yes yes yes yes yes yes Notes: 1) NVE = no visible emissions observed 2) in the table "yes" designates that documentation was completed

Aug 1st-Aug31st QA of CABI daily logs per Colorado Regulation 5.5.7 L (Documentation) and Final Materials Management Plan Page 2 2A and 2B 4 5B 1E 1F Personnel Date Bulk sampling Decontamination Spill Observations Observations Observations Photo-log / documentation visual inspection response of visible of non-earthen of other description and clearance activities emissions / material / indicators of Reponses commented soil impact Lanaia Carveth 8/1/17 Not conducted yes No spills NVE yes yes yes Tyler Godby 8/1/17 Not conducted yes No spills NVE yes yes yes Tyler Godby 8/2/17 Not conducted yes No spills NVE yes yes yes Mitchell Reese 8/2/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/3/17 yes yes No spills NVE yes yes yes Tyler Godby 8/3/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/4/17 Not conducted yes No spills NVE yes yes yes Tyler Godby 8/4/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/5/17 Not conducted yes No spills NVE yes yes yes Tyler Godby 8/7/17 Not conducted yes No spills NVE yes yes yes Tyler Godby 8/8/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/8/17 Not conducted yes No spills NVE yes yes yes Tyler Godby 8/9/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/9/17 Not conducted yes No spills NVE yes yes yes Tyler Godby 8/10/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/10/17 Not conducted yes No spills NVE yes yes yes Tyler Godby 8/11/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/11/17 Not conducted yes No spills NVE yes yes yes Tyler Godby 8/12/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/14/17 Not conducted yes No spills NVE yes yes yes Billy Godby 8/14/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/14/17 Not conducted yes No spills NVE yes yes yes Billy Godby 8/15/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/16/17 Not conducted yes No spills NVE yes yes yes Tyler Godby 8/16/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/17/17 Not conducted yes No spills NVE yes yes yes Tyler Godby 8/17/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/18/17 Not conducted yes No spills NVE yes yes yes Tyler Godby 8/18/17 Not conducted yes No spills NVE yes yes yes Tyler Godby 8/19/17 Not conducted yes No spills NVE yes yes yes

2A and 2B 4 5B 1E 1F Personnel Date Bulk sampling Decontamination Spill Observations Observations Observations Photo-log / documentation visual inspection response of visible of non-earthen of other description and clearance activities emissions / material / indicators of Reponses commented soil impact Lanaia Carveth 8/21/17 Not conducted yes No spills NVE yes yes yes Tyler Godby 8/21/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/22/17 Not conducted yes No spills NVE yes yes yes Billy Godby 8/22/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/23/17 Not conducted yes No spills NVE yes yes yes Tyler Godby 8/23/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/24/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/25/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/26/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/28/17 yes yes No spills NVE yes yes yes Tyler Godby 8/28/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/29/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/30/17 Not conducted yes No spills NVE yes yes yes Tyler Godby 8/30/17 Not conducted yes No spills NVE yes yes yes Lanaia Carveth 8/31/17 Not conducted yes No spills NVE yes yes yes