APPENDIX J. Onsite Methane Report

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1 APPENDIX J Onsite Methane Report

707 Wilshire Boulevard Suite 3250 Los Angeles, CA 90017 213-213-9400 PHONE 818.772.1926 FAX www.trcsolutions.com March 23, 2012 VIA EMAIL SUBMITTAL Mr. Jon Holler Maintenance Design Group, LLC 16 N.

3 707 Wilshire Boulevard Suite 3250 Los Angeles, CA PHONE FAX March 23, 2012 VIA SUBMITTAL Mr. Jon Holler Maintenance Design Group, LLC 16 N. Marengo Avenue, Suite 716 Pasadena, California SITE: RE: PROPOSED EXPOSITION RAIL OPERATIONS AND MAINTENANCE FACILITY STEWART STREET AND EXPOSITION BOULEVARD SANTA MONICA, CALIFORNIA METHANE ASSESSMENT REPORT Dear Mr. Holler: TRC is pleased to submit this Methane Assessment Report for the proposed Exposition Rail Operations and Maintenance Facility to be located at Stewart Street and Exposition Boulevard in Santa Monica, California (Figure 1). Based upon our review of the Los Angeles County Methane Zone Map, the western portion of the property of interest (Figure 2) is located within 1,000 feet of a former landfill, a potential methane source. As a result, there is a concern regarding the possible presence of accumulated methane in the subsurface at the site, which could pose a hazard to future occupants, workers and visitors to the proposed facility. This report includes a listing of objectives, project background, assessment activities, findings, discussion and conclusions and recommendations. 1.0 OBJECTIVES The objectives of this assessment are as follows: Assess the presence and concentrations of methane vapor beneath areas of concern at the site; and Evaluate whether the methane assessment results indicate a potential hazard that warrants preparation or implementation of a Methane Mitigation Plan as part of the site development activities.

4 Mr. Jon Holler Maintenance Design Group, LLC Methane Assessment Report Proposed Exposition Rail Operations and Maintenance Facility Site, Santa Monica, California March 23, PROJECT BACKGROUND Based upon our review of site-related documents provided to TRC including the Preliminary Geotechnical Evaluation (Diaz-Yourman, 2011), Phase II Environmental Site Assessment (Leighton, 2010), and a Phase I Environmental Site Assessment and Historical Site Summary (2008), the area of concern at the subject site consists of a paved asphalt parking lot and portions of two adjacent parcels which cover a combined total area of 420,244 square feet (SF). Both parcels were previously part of the McDonnell-Douglas Aircraft Facility (later Boeing) from The western parcel is currently a parking lot for Santa Monica College but was previously occupied by a parts warehouse during the McDonnell-Douglas era. The eastern parcel was redeveloped in 1971 by GTE and is currently occupied by Verizon facilities, including a warehouse and office structure, a maintenance and auto repair structure, a storage building, a car wash, fuel dispenser-island and a hazardous waste storage shed (see Figure 3 from Leighton, 2010). TRC understands that the proposed development of the site (Figure 3) will include construction of the following features: Main and Secondary Buildings, Traction Power Sub-Station (TPSS), and Wash Building and Cleaning Platform. The cumulative total square footage of these improvements is approximately 76,191 SF. Construction activities associated with the Main and Secondary Buildings will involve excavation, in some areas, to depths of up to 15 feet below grade (fbg). Within other portions of the property, the construction activities would involve excavation of soil to depths of less than 6 fbg. Methane (CH4), a non-toxic, lighter-than-air gas, is a public health and safety concern when present at concentrations in excess of the lower explosive limit (LEL), which is 5% by volume (50,000 parts per million by volume [ppmv]). Due to its potentially explosive characteristic, the concentration of methane typically associated with a significant level of concern is 5,000 ppmv or 10% of the LEL. It is our understanding that the western portion of the property of interest is located within 1,000 feet of a former landfill (County of Los Angeles Department of Public Works, Solid Waste Information Management System ( Historic landfills may generate methane through the anaerobic decomposition of organic matter. As a result, there is a concern regarding the possible presence of methane in the subsurface at the subject site. 2

5 Mr. Jon Holler Maintenance Design Group, LLC Methane Assessment Report Proposed Exposition Rail Operations and Maintenance Facility Site, Santa Monica, California March 23, 2012 Assessment of methane occurrence in the City of Los Angeles is subject to regulations provided under Division 71 of the Los Angeles Municipal Code. These regulations are enforced by the Los Angeles Department of Building and Safety (LADBS) and require at a minimum that site testing be conducted in accordance with their Site Testing Standards for Methane (Information Bulletin 91:7104.1, 2004). It should be noted that the City of Santa Monica has not established its own methane testing or mitigation standards or adopted the County or City of Los Angeles regulations. Consequently, the LADBS Site Testing Standards were used to define the protocols pertaining to the scope of work conducted for this investigation. 3.0 METHANE ASSESSMENT TRC conducted the following activities to investigate areas of concern located on the property. 3.1 PRE-FIELD ACTIVITIES TRC prepared a Site-Specific Health and Safety Plan prior to initiating any field activities at the site. The plan established appropriate protocols and procedures to protect the health and safety of TRC personnel, subcontractors, site employees and the general public during execution of the field work. Prior to initiating any intrusive subsurface activities at the site, the proposed methane probe locations were marked and Underground Service Alert (USA) was notified. USA then contacted the owners of underground utilities in order to mark the ground surface/pavement locations above any of the buried utilities. TRC employed a geophysical survey company to remotely screen the subsurface for buried utilities in the immediate vicinity of the eight boring locations. 3.2 SITE ASSESSMENT ACTIVITIES Vapor Probe Installation On January 19, 2012, TRC installed eight shallow soil vapor probes (TRC-1 through TRC-8) at a depth of 5 fbg using hand augers. At two of the shallow vapor probe locations (TRC-1 and TRC-6), a deep probe was also installed to a depth of 15 fbg using hand auger equipment to 5 fbg and the direct-push method (Geoprobe) to the total depth (see Figure 2). The deep probes were installed in or in close proximity to the areas in which the deepest 15-foot excavations are planned. 3

6 Mr. Jon Holler Maintenance Design Group, LLC Methane Assessment Report Proposed Exposition Rail Operations and Maintenance Facility Site, Santa Monica, California March 23, 2012 Soil samples were collected from the borings at 5-foot intervals for lithologic characterization. A photoionization detector (PID) was used for monitoring the air quality during the investigation and to field screen soil vapor concentrations for volatile organic compounds in the soil samples. The field-screened soil samples were described on soil boring logs in accordance with the Unified Soil Classification System (USCS) by a State of California Professional Geologist. PID readings up to 530 ppmv were only observed in Vapor Probes TRC-1 and TRC-6. A soil sample was collected for laboratory analysis from Vapor Probe TRC-6 for profiling/offsite disposal purposes. This soil sample was collected in a metal sleeve and labeled with the project name, sample ID (including boring number and sample depth), the geologist s initials and the date/time of collection. After the sample was labeled and documented on the chain-ofcustody record, the sample was placed in a cooler with ice to maintain temperature at approximately 4 degrees Celsius ( C) prior to and during transport to Advanced Technology Laboratories, a State of California-certified laboratory, located in Signal Hill, California. The boreholes were saw cut through the asphalt paving using a 12-inch diameter bit. The soil vapor probes were constructed in accordance with the Site Testing Standards for Methane, utilizing 6-inch stainless steel probes, ¼-inch polyethylene tubing, 2-foot screened intervals using #3 sand, bentonite seals, gas-tight quick-connect fittings with stop-cock valves, and trafficrated well boxes. Following placement of the poly tubing, the probe annulus was backfilled with 2 feet of #3 Monterey sand from the bottom of the boring. An annular seal of approximately 3 feet of bentonite clay was placed above the sand. Concrete was placed above the annular seal to approximately 6 inches from ground surface. Finally, a 6-inch flush-mounted, traffic-rated well box was set in concrete at ground surface. Copies of TRC field procedures and the boring logs are included in Attachment 1. Subsequent to probe installation, initial methane concentration readings were taken using a portable Landtec GEM 2000 field instrument. Pressure readings were also obtained from each shallow probe with the Landtec GEM 2000 and using a Magnehelic gauge. TRC was unable to collect soil vapor or pressure readings from TRC-6 (5-foot probe) due to lack of air flow. Refer to Table 2 Field Gas Monitoring Results Soil Vapor Probes, for field vapor and pressure readings Vapor Probe Sample Collection Soil vapor samples were obtained for laboratory analysis from each of the vapor probes on January 24, 2012, following a minimum equilibration period of 24-hours. The samples were collected in 1-liter Tedlar bags for EPA Method 8015M analysis. The Tedlar bag from vapor probe TRC-7 leaked and was re-sampled on January 25. Additionally, on January 25, samples from gas probes TRC-1 (15-foot probe) and TRC-3 were re-filled to increase the volume of gas collected in the sample bags on January 24. Pressure readings were taken again as part of the sampling routine. No sample was collected from TRC-6 (5-foot probe) due to lack of air flow. 4

7 Mr. Jon Holler Maintenance Design Group, LLC Methane Assessment Report Proposed Exposition Rail Operations and Maintenance Facility Site, Santa Monica, California March 23, 2012 Following sample collection from each vapor probe, the Tedlar bags were placed into a black opaque plastic bag and inside a cooler to keep them from direct sunlight and prevent damage to the samples. The samples collected on January 24 and January 25 were transported the same day of collection, via courier, to Air Technology Laboratories, Inc., for methane analysis using EPA Method 8015M. On February 3, 2012, an additional confirmatory sample was taken from TRC-2 using a Summa canister Waste Transport Soil cuttings from the eight borings are temporarily stored on-site in a Department of Transportation (DOT)-approved 55-gallon drum, pending waste characterization. A copy of the waste manifest is included below in Attachment FINDINGS 4.1 LITHOLOGIC FINDINGS Subsurface soils encountered in the borings consisted mainly of low permeability clay and silt. Copies of TRC s soil boring logs are provided in Attachment PRESSURE READINGS The pressure readings observed during sample collections on January 19 and 24, 2012, were nominal and ranged from 0.00 to 0.05 of relative pressure. The pressure readings included in Table 2 were measured using the Landtec GEM 2000, which produced a more accurate reading than the Magnehelic gauge. 4.3 ANALYTICAL RESULTS Concentrations of methane from samples collected on January 24 and 25, 2012, were only detected in one of the eight vapor probes (TRC-2). The soil vapor sample TRC-2-5, obtained from a depth of 5 fbg, had a detected methane concentration of 23 ppmv in the Tedlar bag sample, which slightly exceeded the laboratory reporting limit of 10 ppmv. TRC-2 is located within the footprint of the proposed TPSS. All other vapor samples were non-detect (ND). Although the detected concentration of methane in TRC-2 was minimal (23 ppmv), an additional vapor sample was collected in a Summa canister from TRC-2 on February 3, Summa canisters are generally deployed subsequent to any concentrations detected in samples collected in Tedlar bags to verify the initial analytical results. Methane was detected at 83 ppmv in the Summa canister air sample collected on February 3, Again, such a low concentration is considered to be nominal. Refer to Table 1 Analytical Methane Monitoring Results Soil 5

8 Mr. Jon Holler Maintenance Design Group, LLC Methane Assessment Report Proposed Exposition Rail Operations and Maintenance Facility Site, Santa Monica, California March 23, 2012 Vapor Probes, and the laboratory reports from Air Technology Laboratories, Inc., provided in Attachment 2. TRC collected one soil grab sample from vapor probe boring TRC-6, at 15 fbg, for laboratory analysis due to elevated readings observed on the PID. The sample was analyzed for Title 22 metals, total petroleum hydrocarbons (TPH) by EPA Method 8015M, and volatile organic compounds (VOCs) by EPA Method The metals results we re all within normal background ranges. The organic compound results were all non-detect (ND). Refer to the laboratory report from Advanced Technology Laboratories, Inc., provided in Attachment DISCUSSION 5.1 LIMITED METHANE DETECTION The laboratory sample results indicate methane was detected in only one of the eight vapor probe locations (TRC-2) at nominal concentrations of 23 ppmv in a Tedlar bag sample and 83 ppmv in the Summa canister sample. Vapor Probe TRC-2 is located near the center of the subject site, and all other vapor probe locations were non-detect. Shallow Vapor Probe TRC-6 (5 fbg) was not sampled due to insufficient air flow. The trace concentration of methane detected in TRC-2 is not a cause for concern and, given the lack of methane detections in any of the surrounding vapor probes, it is likely related to localized subsurface decomposition of organic matter in the immediate vicinity of the probe location. Since none of the other probes located west of TRC-2 (in the direction of the former landfill) showed detectable methane concentrations at a detection limit of 10 ppmv, it appears unlikely that the methane detected onsite is related to the former landfill. TRC spoke with a representative from Los Angeles County Department of Health Services regarding requirements for mitigation of methane detected within 1,000 feet of a landfill. The representative discussed the history of the landfill stating that it was a former clay pit (an openpit mine). The clay pit itself was subsequently turned into a landfill (City of Santa Monica Landfill #2), and was operated between 1948 and 1970, used for disposal of burn ash and residential waste. The lithology observed during installation of the vapor probes at the site and in the former clay pit was predominantly clay. This type of lithology has low permeability and, as such, would act as a barrier to inhibit any lateral migration of potential contaminants of concern, including methane. Additionally, TRC spoke with the general contractors (Hathaway-Dinwiddie), who are building a structure across the street, directly west of the site. The site, located at 1800 Stewart Street lies between the Stewart Street Expo site and the former landfill. The contractors informed TRC that the results of the soil vapor survey conducted at their site, prior to commencing construction activities, were all non-detect for methane. 6

9 Mr. Jon Holler Maintenance Design Group, LLC Methane Assessment Report Proposed Exposition Rail Operations and Maintenance Facility Site, Santa Monica, California March 23, CITY OF SANTA MONICA REQUIREMENTS REGARDING METHANE During a telephone conversation with an inspector from the City of Santa Monica Building and Safety (David Mulick, City of Santa Monica, Personal Communication, 2012), regarding the concentration of methane detected in the one probe at the site, TRC was informed that the City does not currently have any regulations regarding the presence of methane. Officials with the Los Angeles County Department of Public Works and the Department of Health services also indicated that the City of Santa Monica has jurisdiction over the Expo Stewart Street site. 6.0 CONCLUSIONS AND RECOMMENDATIONS Only one vapor probe (TRC-2) had a maximum detected concentration (83 ppmv) of methane. The detection limit for methane is 10 ppmv. The lower explosive limit (LEL) for methane is 50,000 ppmv and the standard level of concern is at 10% of the LEL, or 5,000 ppmv. He maximum concentration of 83 ppmv is equivalent to 0.17% of the LEL. Based on these results, a potential fire or explosion hazard due to methane is not currently present beneath the site. There are a number of reasons why the nominal methane detection on site does not appear to be related to the former landfill, which was closed in A trace methane concentration was only detected in one of eight vapor probes at the site. The former landfill site was initially developed as an open pit mine intended to extract the low permeability clay. The laboratory results from vapor probes installed west of TRC-2 (TRC-1, TRC-4 and TRC-5) were all non-detect for methane. No methane was detected from the soil vapor survey conducted at the building site west across Stewart Street, between the Expo site and the former landfill. The concentration of 83 ppmv of methane detected in Vapor Probe TRC-2 is insignificant. The current site conditions do not warrant any mitigation measures. As of the date of this report, the City of Santa Monica Department of Building and Safety does not have any regulations regarding methane. Therefore, TRC does not recommend preparing a Methane Mitigation Plan at this time. In the event that site conditions change in the future or if the City of Santa Monica adopts regulations regarding methane prior to construction of the proposed buildings, a Methane Mitigation Plan for all the enclosed structures at the site may be required. 7

10 Mr. Jon Holler Maintenance Design Group, LLC Methane Assessment Report Proposed Exposition Rail Operations and Maintenance Facility Site, Santa Monica, California March 23, REFERENCES City of Santa Monica Department of Building and Safety, 2012, Personal Communication Regarding Methane Regulations in Santa Monica, January 31, Diaz-Yourman and Associates, 2011, Preliminary Geotechnical Investigation, Exposition Metro Line Maintenance Facility, Santa Monica, California, September 14, Draft Phase II Environmental Site Assessment Report, Exposition Corridor Transit Project Phase 2, Proposed Maintenance Facility, Verizon Santa Monica Yard, 2902 Exposition Boulevard, Santa Monica, California, October 22, Malcolm Pirnie, 2008, Phase 1 Environmental Site Assessment, Verizon California, Inc. Santa Monica Plant Yard, 2902 Exposition Boulevard, Santa Monica, California, August Malcolm Pirnie, 2008, Historical Site Summary, Verizon California, Inc. Santa Monica Plant Yard, 2902 Exposition Boulevard, Santa Monica, California, August

12 Mr. Jon Holler Maintenance Design Group, LLC Methane Assessment Report Proposed Exposition Rail Operations and Maintenance Facility Site, Santa Monica, California March 23, 2012 FIGURES

QUADRANGLE LOCATION 0 1/4 1/2 3/4 1 MILE SCALE

FACILITY STEWART ST. AND EXPOSITION BLVD.

13 QUADRANGLE LOCATION 0 1/4 1/2 3/4 1 MILE SCALE SOURCE: United States Geological Survey 7.5 Minute Topographic Map: Beverly Hills Quadrangle FACILITY: EXPO RAIL OPERATIONS AND MAINTENANCE FACILITY STEWART ST. AND EXPOSITION BLVD. SANTA MONICA, CALIFORNIA INDEX MAP MS=1:1 FILE NAME: Expo_Index Map.dwg FIGURE 1

15 Mr. Jon Holler Maintenance Design Group, LLC Methane Assessment Report Proposed Exposition Rail Operations and Maintenance Facility Site, Santa Monica, California March 23, 2012 TABLES

16 Table 1 Laboratory Analytical Methane Monitoring Results - Soil Vapor Probes Proposed Expo Rail - Operations and Maintenance Facility Stewart Street and Exposition Boulevard, Santa Monica, California Vapor Probe ID Depth (feet) Date CH 4 (ppmv) TRC /24/2012 ND TRC /25/2012 [1] ND TRC /24/ /3/2012 [2] 83 TRC /25/2012 [1] ND TRC /24/2012 ND TRC /24/2012 ND TRC /24/ TRC /24/2012 ND TRC /25/2012 [1] ND TRC /24/2012 ND Notes: Data entry: L. McElhannon CH 4 = Methane by EPA Method 8015M Checked by: L. Arteaga ppmv = parts per million by volume ND = Not detected (below reporting limit of 10 ppmv) -- = Unable to collect reading - no air flow [1] = Tedlar bag from TRC-7, collected on 1/24/12, leaked. Collected new sample on 1/25/12. Collected additional sample volume in Tedlar bags from TRC-1-15 and TRC-3-5 on 1/25/12. [2] = Sample collected using a Summa canister Expo Stewart St\ Methane Tables\Table 1.xls Page 1 of 1

17 Table 2 Field Gas Monitoring Results - Soil Vapor Probes Proposed Expo Rail - Operations and Maintenance Facility Stewart Street and Exposition Boulevard, Santa Monica, California Vapor Probe ID Fixed Gases Fixed Gases Fixed Gases Depth (feet) Date (% v/v) P Date (% v/v) P Date (% v/v) P CO 2 O 2 CH 4 CO 2 O 2 CH 4 CO 2 O 2 CH 4 TRC /19/ /24/ /25/2012 NA NA NA NA TRC /19/ /24/ /25/ NA TRC /19/ /24/ /25/2012 NA NA NA NA TRC /19/ /24/ /25/ NA TRC /19/ /24/ /25/2012 NA NA NA NA TRC /19/ /24/ /25/2012 NA NA NA NA TRC /19/ /24/ /25/2012 NA NA NA NA TRC /19/ /24/ /25/2012 NA NA NA NA TRC /19/ /24/ /25/ NA TRC /19/ /24/ /25/2012 NA NA NA NA Notes: Field readings obtained using a Landtec GEM 2000 on 1/19/12, 1/24/12 and 1/25/12 %V/V = percent of volume of constituent divided by the volume of all the constituents CO 2 = Carbon Dioxide O 2 = Oxygen CH 4 = Methane P = Pressure (millibars of relative pressure) -- = Unable to collect reading - no air flow NA = No reading was taken Data Entry: L. Arteaga Checked by: L. McElhannon Expo Stewart St\ Methane Tables\Table 2.xls Page 1 of 1

18 Mr. Jon Holler Maintenance Design Group, LLC Methane Assessment Report Proposed Exposition Rail Operations and Maintenance Facility Site, Santa Monica, California March 23, 2012 ATTACHMENT 1 GENERAL FIELD PROCEDURES, BORING LOGS AND SOIL DISPOSAL MANIFEST

19 GENERAL FIELD VAPOR PROBE INSTALLATION PROTOCOL SOIL VAPOR PROBE INSTALLATION Borings are advanced into soil using a direct-push drilling rig such as a Geoprobe to the desired sample collection depth. Following hand-auger advancement, soil vapor probes are advanced into the undisturbed soil by the Geoprobe to desired depth. The soil vapor probes are constructed of 0.5-inch stainless steel tip. An inert 1/4-inch ID, polyethylene tube is threaded down the center of the probe and connected to a sampling port just above the steel tip. Once inserted to the desired depth, the probe is drawn back slightly to open the tip and expose the stainless steel sample screen. This design prevents clogging of the sampling ports and crosscontamination from soils during insertion.

29 Mr. Jon Holler Maintenance Design Group, LLC Methane Assessment Report Proposed Exposition Rail Operations and Maintenance Facility Site, Santa Monica, California March 23, 2012 ATTACHMENT 2 LABORATORY REPORTS AND CHAIN OF CUSTODY FORMS

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63 Mr. Jon Holler Maintenance Design Group, LLC Methane Assessment Report Proposed Exposition Rail Operations and Maintenance Facility Site, Santa Monica, California March 23, 2012 ATTACHMENT 3 LOS ANGELES ORDINANCE NO

APPENDIX K. Groundwater Monitoring Results

APPENDIX K. Groundwater Monitoring Results APPENDIX K Groundwater Monitoring Results RESULTS OF SOIL GAS INVESTIGATION The McKinley Village Property Sacramento, California Prepared for: RCI McKinley, LLC and Holland & Knight, LLP 13 June 2013