DRAFT. Phase I Environmental Site Assessment 977 Danville Boulevard Alamo, California. Location

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1 Type of Services Location Phase I Environmental Site Assessment Client Dutra Land & Consulting Services, Inc. Client Address Mission Blvd, Suite 230 Fremont, California Project Number Date September 14, 2017 DRAFT Prepared by Sarah E. Kalika, P.G. Senior Project Geologist Christopher J. Heiny, P.G. Principal Geologist

2 Table of Contents SECTION 1: INTRODUCTION PURPOSE SCOPE OF WORK ASSUMPTIONS ENVIRONMENTAL PROFESSIONAL... 2 SECTION 2: SITE DESCRIPTION LOCATION AND OWNERSHIP CURRENT/PROPOSED USE OF THE PROPERTY SITE SETTING AND ADJOINING SITE USE... 3 SECTION 3: USER PROVIDED INFORMATION CHAIN OF TITLE ENVIRONMENTAL LIENS OR ACTIVITY AND USE LIMITATIONS SPECIALIZED KNOWLEDGE AND/OR COMMONLY KNOWN OR REASONABLY ASCERTAINABLE INFORMATION... 4 SECTION 4: RECORDS REVIEW STANDARD ENVIRONMENTAL RECORD SOURCES On-Site Database Listings Adjoining Property Database Listings and Nearby Spill Incidents ADDITIONAL ENVIRONMENTAL RECORD SOURCES City and County Agency File Review Division of Oil, Gas and Geothermal Resources Maps... 5 SECTION 5: PHYSICAL SETTING RECENT USGS TOPOGRAPHIC MAP HYDROGEOLOGY... 6 SECTION 6: HISTORICAL USE INFORMATION HISTORICAL SUMMARY OF SITE HISTORICAL SUMMARY OF SITE VICINITY... 7 SECTION 7: SITE RECONNAISSANCE METHODOLOGY AND LIMITING CONDITIONS OBSERVATIONS Site Photographs SECTION 8: ENVIRONMENTAL QUESTIONNAIRE AND INTERVIEWS ENVIRONMENTAL QUESTIONNAIRE / OWNER INTERVIEW INTERVIEWS WITH PERSON(S) KNOWLEDGEABLE OF SITE USE INTERVIEWS WITH PREVIOUS OWNERS AND OCCUPANTS SECTION 9: PRELIMINARY SOIL QUALITY EVALUATION SOIL SAMPLE COLLECTION AND LABORATORY ANALYSES ENVIRONMENTAL SCREENING CRITERIA SOIL ANALYTICAL RESULTS SECTION 10: FINDINGS, OPINIONS AND CONCLUSIONS (WITH RECOMMENDATIONS) HISTORICAL SITE USAGE CHEMICAL STORAGE AND USE AGRICULTURAL USE SOIL QUALITY Former Orchard Areas Adjacent to Structures Page i

3 Soil Removal and Regulatory Considerations IMPORTED SOIL ENVIRONMENTAL ATTORNEY ASBESTOS CONTAINING BUILDING MATERIALS (ACMS) LEAD-BASED PAINT DATA GAPS DATA FAILURES RECOGNIZED ENVIRONMENTAL CONDITIONS SECTION 11: LIMITATIONS FIGURE 1 VICINITY MAP FIGURE 2 SITE PLAN APPENDIX A TERMS AND CONDITIONS APPENDIX B USER-PROVIDED INFORMATION APPENDIX C DATABASE SEARCH REPORT APPENDIX D HISTORIC AERIAL PHOTOGRAPHS AND MAPS APPENDIX E LOCAL STREET DIRECTORY SEARCH RESULTS APPENDIX F RECORDS REVIEW DOCUMENTS APPENDIX G OWNER QUESTIONNAIRE APPENDIX H LABORATORY ANALYTICAL REPORTS Page ii

4 DRAFT Type of Services Location Phase I Environmental Site Assessment SECTION 1: INTRODUCTION This report presents the results of the Phase I Environmental Site Assessment (ESA) performed for the existing residential property described as Contra Costa County assessor s parcel number (APN) at in (Site) and as shown on Figures 1 and 2. This work was performed for Dutra Land & Consulting Services, Inc. (Dutra) in accordance with our August 28, 2017 Agreement (Agreement). 1.1 PURPOSE The scope of work presented in the Agreement was prepared in general accordance with ASTM E titled, Standard Practice for Environmental Site Assessments: Phase I Environmental Site Assessment Process (ASTM Standard). The ASTM Standard is in general compliance with the Environmental Protection Agency (EPA) rule titled, Standards and Practices for All Appropriate Inquiries; Final Rule (AAI Rule). The purpose of this Phase I ESA is to strive to identify, to the extent feasible pursuant to the scope of work presented in the Agreement, Recognized Environmental Conditions at the property. As defined by ASTM E , the term Recognized Environmental Condition means the presence or likely presence of any hazardous substances or petroleum products in, on, or at a property: (1) due to any release to the environment; (2) under conditions indicative of a release to the environment; or (3) under conditions that pose a material threat of a future release to the environment. De minimis conditions are not Recognized Environmental Conditions. Cornerstone Earth Group, Inc. (Cornerstone) understands that Dutra intends to purchase the property for residential development. We performed this Phase I ESA to support Dutra in evaluation of Recognized Environmental Conditions at the Site. This Phase I ESA is intended to reduce, but not eliminate, uncertainty regarding the potential for Recognized Environmental Conditions at the Site. 1.2 SCOPE OF WORK As presented in our Agreement, the scope of work performed for this Phase I ESA included the following: A reconnaissance of the Site to note readily observable indications of significant hazardous materials releases to structures, soil or ground water. Page 1

5 Drive-by observation of adjoining properties to note readily apparent hazardous materials activities that have or could significantly impact the Site. Acquisition and review of a regulatory agency database report of public records for the general area of the Site to evaluate potential impacts to the Site from reported contamination incidents at nearby facilities. Review of readily available information on file at selected governmental agencies to help evaluate past and current Site use and hazardous materials management practices. Review of readily available maps and aerial photographs to help evaluate past and current Site uses. Interviews with persons reportedly knowledgeable of existing and prior Site uses, including the current Site operator(s). Preparation of a written report summarizing our findings and recommendations. The limitations for the Phase I ESA are presented in Section 10; the terms and conditions of our Agreement are presented in Appendix A. 1.3 ASSUMPTIONS In preparing this Phase I ESA, Cornerstone assumed that all information received from interviewed parties is true and accurate. In addition, we assumed that all records obtained by other parties, such as regulatory agency databases, maps, related documents and environmental reports prepared by others are accurate and complete. We also assumed that the boundaries of the Site, based on information provided by Dutra are as shown on Figure 2. We have not independently verified the accuracy or completeness of any data received. 1.4 ENVIRONMENTAL PROFESSIONAL This Phase I ESA was performed by Sarah E. Kalika, P.G. and Christopher J. Heiny, P.G., Environmental Professionals who meet the qualification requirements described in ASTM E and 40 CFR based on professional licensing, education, training and experience to assess a property of the nature, history and setting of the Site. SECTION 2: SITE DESCRIPTION This section describes the Site as of the date of this Phase I ESA. The location of the Site is shown on Figures 1 and 2. Tables 1 through 3 summarize general characteristics of the Site and adjoining properties. The Site is described in more detail in Section 7, based on our on-site observations. 2.1 LOCATION AND OWNERSHIP Table 1 describes the physical location, and ownership of the property, based in part on information provided by Dutra. Page 2

6 Table 1. Location and Ownership Assessor s Parcel No. (APN) Reported Address/Location, Alamo Owner Xavier Limited Partnership Approximate Lot Size 3.7 acres Approximate Bldg. Size Five separate structures, per County: 6,177 square feet Construction Date CURRENT/PROPOSED USE OF THE PROPERTY The current and proposed uses of the property are summarized in Table 2. Table 2. Current and Proposed Uses Current Use Proposed Use Residential Residential 2.3 SITE SETTING AND ADJOINING SITE USE Land use in the general Site vicinity appears to be primarily single-family residential. Based on our Site vicinity reconnaissance, adjoining Site uses are summarized below in Table 3. Table 3. Adjoining Site Uses North South East West Danville Boulevard, with single-family residential further north Iron Horse Trail (recreational trail, former railroad tracks) Single-family residential Single-family residential SECTION 3: USER PROVIDED INFORMATION The ASTM standard defines the User as the party seeking to use a Phase I ESA to evaluate the presence of Recognized Environmental Conditions associated with a property. For the purpose of this Phase I ESA, the User is Dutra. The All Appropriate Inquiries Final Rule (40 CFR Part 312) requires specific tasks be performed by or on behalf of the party seeking to qualify for Landowner Liability Protection under CERCLA liability (i.e, the User). Per the ASTM standard, if the User has information that is material to Recognized Environmental Conditions, such information should be provided to the Environmental Professional. This information includes: 1) specialized knowledge or experience of the User, 2) commonly known or reasonably ascertainable information within the local community, and 3) knowledge that the purchase price of the Site is lower than the fair market value due to contamination. A search of title records for environmental liens and activity and use limitations also is required. Page 3

7 3.1 CHAIN OF TITLE A chain-of-title was not provided for our review. 3.2 ENVIRONMENTAL LIENS OR ACTIVITY AND USE LIMITATIONS An environmental lien is a financial instrument that may be used to recover past environmental cleanup costs. Activity and use limitations (AULs) include other environmental encumbrances, such as institutional and engineering controls. Institutional controls (ICs) are legal or regulatory restrictions on a property s use, while engineering controls (ECs) are physical mechanisms that restrict property access or use. The regulatory agency database report described in Section 4.1 did not identify the Site as being in 1) US EPA databases that list properties subject to land use restrictions (i.e., engineering and institutional controls) or Federal Superfund Liens or 2) lists maintained by the California Department of Toxic Substances Control (DTSC) of properties that are subject to AULs or environmental liens where the DTSC is a lien holder. Cornerstone reviewed a Preliminary Title Report prepared for the Site by Chicago Title Company, dated May 30, No environmental liens or records of ownership (including leases) indicative of significant hazardous materials use associated with the Site were listed in the title report. A copy of the title report is included in Appendix B. 3.3 SPECIALIZED KNOWLEDGE AND/OR COMMONLY KNOWN OR REASONABLY ASCERTAINABLE INFORMATION Based on information provided by or discussions with Dutra we understand that Dutra does not have such specialized knowledge or experience, commonly known or reasonably ascertainable information regarding the Site, or other information that is material to Recognized Environmental Conditions. SECTION 4: RECORDS REVIEW 4.1 STANDARD ENVIRONMENTAL RECORD SOURCES Cornerstone conducted a review of federal, state and local regulatory agency databases provided by Environmental Data Resources (EDR) to evaluate the likelihood of contamination incidents at and near the Site. The database sources and the search distances are in general accordance with the requirements of ASTM E A list of the database sources reviewed, a description of the sources, and a radius map showing the location of reported facilities relative to the project Site are attached in Appendix C. The purpose of the records review is to obtain reasonably available information that will help identify Recognized Environmental Conditions. Accuracy and completeness of record information varies among information sources, including government sources. Record information is often inaccurate or incomplete. The Environmental Professional is not obligated to identify mistakes or insufficiencies or review every possible record that might exist with the Site. The customary practice is to review information from standard sources that is reasonably available within reasonable time and cost constraints. Page 4

8 4.1.1 On-Site Database Listings The Site was not identified within databases searched by EDR Adjoining Property Database Listings and Nearby Spill Incidents No adjacent properties or other off-site spill incidents were reported that appear likely to significantly impact soil, soil vapor, or ground water beneath the Site. The potential for impact was based on our interpretation of the types of incidents, the locations of the reported incidents in relation to the Site and the assumed ground water flow direction. 4.2 ADDITIONAL ENVIRONMENTAL RECORD SOURCES The following additional sources of readily ascertainable public information for the Site also were reviewed during this Phase I ESA City and County Agency File Review Cornerstone requested available files pertaining to at the following public agencies: Contra Costa County Building Department (CCCBD), Contra Costa County Environmental Health - Hazardous Materials (CCCEHD), and San Francisco Bay Regional Water Quality Control Board (Water Board). The Contra Costa County Environmental Health Department Hazardous Materials Division issues permits for USTs, exploratory borings, and well installations; and oversees investigations of spills and cleanups. The information reviewed is summarized in Table 5; selected documents are provided in Appendix F. CCCEHD reported that no files were available for the Site address. The Water Board did not have files other than information available on Geotracker. CCCBD provided a permit summary for the Site address of as included in Table 5. Table 5. File Review Information Agency Name Date Address Occupant Remarks CCCBD Danville Blvd Not reported Replace gas line from meter to Unit #E by a contractor Division of Oil, Gas and Geothermal Resources Maps To evaluate the presence of oil or gas wells on-site and in the immediate Site vicinity, maps available on-line at the California Department of Conservation, Division of Oil, Gas, and Geothermal Resources (DOGGR) ( were reviewed. No wells were depicted within Township 01S, Range 01W, Section 18. Page 5

9 SECTION 5: PHYSICAL SETTING We reviewed readily available geologic and hydrogeologic information to evaluate the likelihood that chemicals of concern released on a nearby property could pose a significant threat to the Site and/or its intended use. 5.1 RECENT USGS TOPOGRAPHIC MAP A 2012 USGS 7.5 minute topographic map was reviewed to evaluate the physical setting of the Site. The Site s elevation is approximately 325 feet above mean sea level; topography in the vicinity of the Site slopes gradually downward to the east-northeast toward San Ramon Creek. 5.2 HYDROGEOLOGY The ground water depth and flow direction has not been evaluated beneath the Site. Ground water measurements were attempted at nearby properties (Ball Ranch [300 Camille Avenue, approximately 1,500 feet southwest of the Site and at a higher elevation] and Danala Farms [950 Danville Blvd, approximately 300 feet east of the Site]). Ground water reportedly was not encountered at depths up to 35 feet at the Ball Ranch property (Engeo, 2010) and at depths of up to 7½ feet at the Danala Farms property (Aqua Science Engineers, 1988). The ground water flow direction in the Site vicinity is likely to be east-northeast toward San Ramon Creek. SECTION 6: HISTORICAL USE INFORMATION The objective of the review of historical use information is to develop a history of the previous uses of the Site and surrounding area in order to help identify the likelihood of past uses having led to Recognized Environmental Conditions at the property. The ASTM standard requires the identification of all obvious uses of the property from the present back to the property s first developed use, or back to 1940, whichever is earlier, using reasonably ascertainable standard historical sources. 6.1 HISTORICAL SUMMARY OF SITE The historical sources reviewed are summarized below. The results of our review of these sources are summarized in Table 6. Historical Aerial Photographs: We reviewed aerial photographs dated between 1946 and 2012 obtained from EDR of Milford, Connecticut; copies of aerial photographs reviewed are presented in Appendix D. Historical Topographic Maps: We reviewed USGS 15-minute and 7.5-minute historic topographic maps dated 1896, 1897, 1912, 1915, 1947, 1948, 1949, 1959, 1968, 1973, 1980, 1996, 1999, and 2012; copies of historic topographic maps reviewed are presented in Appendix D. Historical Fire Insurance Maps: EDR reported that the Site was not within the coverage area of fire insurance maps. Local Street Directories: We reviewed city directories obtained from EDR that were researched at approximately 5 year intervals between 1975 and 2013 to obtain Page 6

10 information pertaining to past Site occupants. The city directory summary is presented in Appendix E. Table 6. Summary of Historical Source Information for Site Date Source Comment 1896/1897, Topographic Site is situated between a railroad track adjacent to the 1915 Map southwest, and another adjacent to the northeast. No 1946, 1949 Aerial photographs 1947, 1949 Topographic Map 1948 Topographic Map 1959 Topographic Map 1950, 1958, Aerial 1966 photographs structures depicted on-site. Site developed with an orchard. Several structures observed in the central and southwestern portion of Site. Railroad track observed along the southwestern boundary. Roadway depicted along the northeastern border. Site depicted within an agricultural area, three structures depicted on-site. A railroad track is depicted adjacent to the southwest. Site depicted with one structure on-site, with a railroad track adjacent to the southwest. Site depicted as within orchards, one structure on-site, railroad track adjacent to the southwest. Site developed with an orchard. Several structures observed in the central and southwestern portion of Site. Railroad track observed along the southwestern boundary. Roadway depicted along the northeastern border. 1968, 1973 Topographic Map Site depicted as within a developed area, one structure on- Site, railroad track adjacent to the southwest. 1975, 1980, City Directory Residential occupants reported 1985, 1989, 1992, Aerial Most of the orchard is no longer observed on-site. photograph 1980 Topographic Map One structure depicted on Site. Railroad track no longer depicted. 1982, 1993, 1998 Aerial photographs Several structures observed along with two large trees and several smaller trees in the center and southwest portion of the Site. 1999, 2003 City Directory Residential occupants and Pemberley Couture reported 1996, 1999, 2012 Topographic Map Site depicted as within a developed area with no specific structures depicted. 2005, 2006, 2009 Aerial photographs Four to five structures observed in the central and southwestern portion of the Site. 2008, 2013 City Directory Residential occupants reported 2010 Aerial photographs Four to five structures observed in the central and southwestern portion of the Site Aerial photograph 6.2 HISTORICAL SUMMARY OF SITE VICINITY Site developed with several structures and large trees in the central and southwestern portion of the Site. Remainder of Site is dry grass. A paved trail is observed adjacent to the southwest, in the location of the former railroad track. Based on our review of the information described in Section 6.1, the general Site vicinity was originally mainly rural residential properties with orchards. A railroad line extended through the Page 7

11 valley in the approximate location of present-day Danville Boulevard until the late 1940 s and in the location of the Iron Horse Trail until the 1970 s. The Iron Horse Trail is a paved recreational trail, observed adjacent to the Site. The vicinity transitioned from a rural area with orchards to a residential from the 1960 s through the 1980 s. The area is now primarily occupied by singlefamily residential properties. SECTION 7: SITE RECONNAISSANCE We performed a Site reconnaissance to evaluate current Site conditions and to attempt to identify Site Recognized Environmental Conditions. The results of the reconnaissance are discussed below. Additional Site observations are summarized in Table 7 in Section 7.2. Photographs of the Site are presented in Section METHODOLOGY AND LIMITING CONDITIONS To observe current Site conditions (readily observable environmental conditions indicative of a significant release of hazardous materials), Cornerstone staff Sarah E. Kalika visited the Site on August 30, 2017 and was unaccompanied. The Site reconnaissance was conducted by walking representative areas of the Site, including the Site periphery. Cornerstone staff only observed those areas that were reasonably accessible, safe, and did not require movement of equipment, debris, or other objects. Cornerstone did not enter any structures, by request of the property owner. 7.2 OBSERVATIONS At the time of our Site visit, the Site was developed with one main residence in the central portion of the Site. Three additional residential structures and two detached garage / shed units were observed west of the main structure. Two shipping containers were observed south of the main house. An asphalt-paved driveway extended from the entry along Danville Boulevard to the main house and circled behind a fenced backyard area to provide access to the additional residential structures and garage / sheds. Boxes and plastic containers of household items were observed in the vicinity of the two shipping containers and one garage. Other garages contained gardening equipment, tools, and furniture. Electricity was provided to the Site by overhead wires. Four natural gas meters were observed north of the main residence. The Site is reportedly served by at least one septic tank. Cornerstone did not enter any structures as requested by the property owner and, therefore, we could not view the interior contents of these structures. Cornerstone was also not able to view the exterior driveway area west of the main house (Photograph 13) and the area between the two shipping containers (Photograph 5). Both of these areas were obstructed due to the presence of large amounts of household items, personal belongings, and tools. Cornerstone did not attempt to move tenant objects to view surfaces beneath. The remainder of the Site was undeveloped and covered with dry grass, trees, and shrubs. Page 8

12 Cornerstone observed the asphalt-paved Iron Horse Trail along the southwestern boundary of the Site; single-family residences along the northwest, north, and southeast Site borders; and Danville Boulevard along the northeastern border. Table 7. Summary of Readily Observable Site Features General Observation Aboveground Storage Tanks Agricultural Wells Air Emission Control Systems Boilers Burning Areas Chemical Mixing Areas Chemical Storage Areas Clean Rooms Drainage Ditches Elevators Emergency Generators Equipment Maintenance Areas Fill Placement Ground Water Monitoring Wells High Power Transmission Lines Hoods and Ducting Hydraulic Lifts Incinerator Petroleum Pipelines Petroleum Wells Ponds or Streams Railroad Lines Row Crops or Orchards Stockpiles of Soil or Debris Sumps or Clarifiers Transformers Underground Storage Tanks Vehicle Maintenance Areas Vehicle Wash Areas Wastewater Neutralization Systems Comments, but possibly present due to age of Site, Iron Horse Trail (adjacent, as described above) is a former railroad line. The comment does not warrant that these features are not present on-site; it only indicates that these features were not readily observed during the Site visit. Page 9

13 7.2.1 Site Photographs Photograph 1. View looking west-southwest along entrance driveway of Site from Danville Boulevard. Photograph 2. View looking north-northeast along Danville Boulevard (the eastern Site boundary). Page 10

14 Photograph 3. View looking west across southern portion of Site. Photograph 4. Exterior view of main residence in central portion of Site. Page 11

15 Photograph 5. Two shipping containers, various household items stored in portable boxes, packing boxes, and debris. Photograph 6. View looking south from central portion of Site. Page 12

16 Photograph 7. View looking southwest along driveway toward additional residences and garages. Photograph 8. Metal storage sheds located southwest of main residence. Page 13

17 Photograph 9. Tools within one of metal storage sheds. Photograph 10. Household fixtures stored within fenced backyard of main residence. Page 14

18 Photograph 11. Furniture stored within portion of one garage. Photograph 12. Additional household furniture and items stored within portion of one garage. Page 15

19 Photograph 13. Additional residence and garage, household items stored in tents along western portion of property west of main residence. Photograph 14. Household items stored in boxes outside garage area of secondary residence. Page 16

20 Photograph 15. Household items stored within garage of secondary residence. Photograph 16. Detached garage to the north of secondary residence/garage and south of third observed residence. Page 17

21 Photograph 17. Interior of detached garage from photograph 16. Photograph 18. Third observed residence located northwest of main residence. Page 18

22 Photograph 19. View looking northwest at third residence. Photograph 20. Fourth observed residence located north of main residence. Page 19

23 Photograph 21. View looking east at trash bins and debris along northern driveway and northern side of main residence. Photograph 22. View looking northeast across northern portion of Site. Page 20

24 Photograph 23. Four natural gas meters located north of the main residence. SECTION 8: ENVIRONMENTAL QUESTIONNAIRE AND INTERVIEWS 8.1 ENVIRONMENTAL QUESTIONNAIRE / OWNER INTERVIEW To help obtain information on current and historical Site use and use/storage of hazardous materials on-site, we provided an environmental questionnaire to Dutra, who was asked to forward the questionnaire to the Site owner for completion. The completed questionnaire is attached in Appendix G. Trustee for the Xavier Limited Partnership, Sharon Xavier de Sousa, completed the environmental questionnaire to report her knowledge of the Site. Ms. Xavier de Sousa reported that the Site has been developed with residential structures since at least the 1930 s and walnut trees were previously located on-site. She reported that the Site is served by two septic tanks and one septic tank was capped. She additionally stated that there was a gas pump on-site that was removed in the 1960 s. The locations of the septic tanks and former gas pump were not reported. She reported that she was not aware of any environmental liens, environmental cleanups, or land use restrictions pertaining to the Site. 8.2 INTERVIEWS WITH PERSON(S) KNOWLEDGEABLE OF SITE USE Ms. Xavier de Sousa, trustee for the Xavier Limited Partnership, completed the environmental questionnaire, as discussed above. Page 21

25 8.3 INTERVIEWS WITH PREVIOUS OWNERS AND OCCUPANTS Contact information for previous Site owners and occupants was not provided to us. Therefore, interviews with previous Site owners and occupants could not be performed. SECTION 9: PRELIMINARY SOIL QUALITY EVALUATION Cornerstone performed a preliminary soil quality evaluation to determine if the historic agricultural use impacted soil quality. Additionally, Cornerstone collected additional samples adjacent to the existing buildings to determine if past termiticide spraying (if applied) and/or weathering of lead paint (if present) impacted the shallow soil quality. 9.1 SOIL SAMPLE COLLECTION AND LABORATORY ANALYSES On September 5, 2017, Cornerstone collected soil samples from 10 borings (SS-1 through SS- 10) advanced using hand sampling equipment. Soil samples SS-1 through SS-5 were collected in open field areas to evaluate soil quality in former orchard areas. Soil samples SS-6 through SS-10 were collected adjacent to existing structures. The samples were collected from the upper approximately ½ foot of soil in new stainless steel liners, the ends covered in Teflon film, capped, taped, and labeled. The samples were placed in an ice-chilled cooler for transportation to a state-certified laboratory. The soil samples collected from the upper approximately ½ foot of soil were analyzed for organochlorine pesticides (OCPs, EPA Test Method 8081), arsenic, mercury and lead (EPA Method 6010/7000). 9.2 ENVIRONMENTAL SCREENING CRITERIA Detected compounds are presented in Table A (OCPs and Metals). Chain of custody documentation and laboratory analytical reports are presented in Appendix H. The results were compared to the residential screening levels (DTSC-SL) recommended in the DTSC Office of Human and Ecological Risk (HERO) guidance document Human Health Risk Assessment Note 3 (2016). For parameters and compounds where no DTSC-SLs are established, the detected compounds were compared to the residential Regional Screening Levels (RSLs) established by the USEPA Region 9 (USEPA, June 2017) using a Hazard Quotient (HQ) of 1. Arsenic concentrations were compared to their published background ranges. The screening levels and background concentrations used are provided in the attached tables. The total concentrations of DDT and chlordane detected were also compared to the Total Threshold Limit Concentration (TTLC) values for determination of a non-resource Conservation and Recovery Act (RCRA) (California) hazardous waste. These comparative values are provided in the attached tables. 9.3 SOIL ANALYTICAL RESULTS A summary of the soil quality analytical results is provided below: Pesticides Chlordane was detected at concentrations up to 5.0 mg/kg (SS-10, ½ foot), and exceeded its residential RSL in 4 of 10 samples analyzed. The detected chlordane Page 22

26 concentrations in samples SS-7 (0-½ foot) and SS-10 (0-½ foot) also exceeded the TTLC value of 2.5 mg/kg. Dieldrin was detected above the residential RSL in 1 of 10 samples, at a concentration of mg/kg (SS-9, ½ foot). The remaining OCPs were detected at concentrations below their respective residential screening criteria. Metals Arsenic was detected at concentrations up to 51 mg/kg (SS-4, ½ foot) and exceeded its published background concentration of 11 mg/kg in 5 of 10 samples analyzed. Lead was detected at concentrations up to 880 mg/kg (SS-5 at ½ foot), and exceeded its residential DTSC-SL of 80 mg/kg in 5 of 10 samples analyzed. SECTION 10: FINDINGS, OPINIONS AND CONCLUSIONS (WITH RECOMMENDATIONS) Cornerstone performed this Phase I ESA in general accordance to ASTM E to support Dutra in evaluation of Recognized Environmental Conditions. Our findings, opinions and conclusions are summarized below HISTORICAL SITE USAGE Based on the information obtained during this study, the Site appears to have been developed since approximately the 1940 s with a rural residence and orchard. Additional residential structures and garages were added in the 1950 s and 1960 s. The orchard was no longer present by the late 1970 s. The general Site vicinity was originally mainly rural residential properties with orchards. A railroad line extended through the valley in the approximate location of present-day Danville Boulevard until the late 1940 s and in the location of the Iron Horse Trail until the 1970 s. The Iron Horse Trail is currently a paved recreational trail, observed adjacent to the Site. The vicinity transitioned from a rural area with orchards to residential from the 1960 s through the 1980 s. The area is now primarily occupied by single-family residential properties CHEMICAL STORAGE AND USE No significant quantities of hazardous materials were observed at the Site during our visit. Typical household cleaning supplies also are presumably used within the residential units. These materials are not likely to significantly impact soil or ground water quality beneath the Site provided that they are used in accordance with the manufacturer s instructions. A representative of the current owner reported the former presence of a gas pump on-site, but the location of this pump was not indicated. If the gas pump was associated with an above ground (AST) or underground fuel tank (UST), soil in the vicinity of the former tank and pump equipment may be impacted with petroleum hydrocarbons. No records were found to indicate the presence of a fuel tank or pump on the Site. The location of the former gas pump and any associated fuel tank(s) should be investigated further. Page 23

27 10.3 AGRICULTURAL USE The Site was previously used as an orchard from the 1940 s until the 1970 s. Pesticides may have been applied to crops in the normal course of farming operations. Soil quality is discussed below SOIL QUALITY Former Orchard Areas Laboratory analyses of soil samples collected from former orchard areas (SS-1 through SS-5) did not detect OCPs, lead or mercury exceeding residential screening criteria. Arsenic was detected in 4 of 5 samples at or above the published background (11 mg/kg), with a maximum concentration of 51 mg/kg detected. We recommend collecting additional soil samples to evaluate the vertical and lateral extent of the elevated arsenic Adjacent to Structures Lead (5 of 5 samples), arsenic (1 of 5 samples), chlordane (4 of 5 samples) and dieldrin (1 of 5 samples) were detected exceeding residential screening levels in samples collected from adjacent to structures (SS-6 through SS-10). Concentrations of total lead detected (up to 880 mg/kg) are less than the California hazardous waste limit of 1,000 mg/kg, but likely exceed the soluble (STLC) limit for California hazardous waste. Chlordane exceeded the TTLC of 2.5 mg/kg in two samples. The OCPs and lead detected may be associated with termiticide spraying around the structures and weathering of lead paint, respectively Soil Removal and Regulatory Considerations We recommend removal of soil exceeding residential screening levels and, for arsenic, background levels, prior developing the Site. We additionally recommend engaging a regulatory agency for oversight of the soil removal activities IMPORTED SOIL If planned development will require importing soil, we recommend documenting the source and quality of imported soil. The DTSC s October 2001 Clean Fill Advisory provides useful guidance on evaluating imported fill ENVIRONMENTAL ATTORNEY Due to known Recognized Environmental Conditions at the Site, we recommend consulting with an environmental attorney regarding liabilities associated with acquiring the Site ASBESTOS CONTAINING BUILDING MATERIALS (ACMS) Due to the age of the on-site structures, building materials may contain asbestos. If demolition, renovation, or re-roofing of the building is planned, an asbestos survey is required by local authorities and/or National Emissions Standards for Hazardous Air Pollutants (NESHAP) guidelines. NESHAP guidelines require the removal of friable and potentially friable ACMs prior to building demolition or renovation that may disturb the ACM. Page 24

28 10.8 LEAD-BASED PAINT The Consumer Product Safety Commission banned the use of lead as an additive in paint in Based on the age of the buildings, lead-based paint may be present. If demolition is planned, the removal of lead-based paint isn t required if it is bonded to the building materials. However, if the lead-based paint is flaking, peeling, or blistering, it should be removed prior to demolition. In either case, applicable OSHA regulations must be followed; these include requirements for worker training, air monitoring and dust control, among others. Any debris or soil containing lead must be disposed appropriately DATA GAPS ASTM Standard Designation E requires the Environmental Professional to comment on significant data gaps that affect our ability to identify Recognized Environmental Conditions. A data gap is a lack of or inability to obtain information required by ASTM Standard Designation E despite good faith efforts by the Environmental Professional to gather such information. A data gap by itself is not inherently significant; it only becomes significant if it raises reasonable concerns. The following data gaps were identified: Contact information for the former owners of the Site were not provided to us. Thus, former occupants and owners were not interviewed during this study. The general environmental setting of the Site appears to have been established based on the information reviewed from other data sources. We do not consider this data gap to be significant DATA FAILURES As described by ASTM Standard Designation E , a data failure occurs when all of the standard historical sources that are reasonably ascertainable and likely to be useful have been reviewed and yet the historical research objectives have not been met. Data failures are not uncommon when attempting to identify the use of a Site at five-year intervals back to the first use or to 1940 (whichever is earlier). ASTM Standard Designation E requires the Environmental Professional to comment on the significance of data failures and whether the data failure affects our ability to identify Recognized Environmental Conditions. A data failure by itself is not inherently significant; it only becomes significant if it raises reasonable concerns. The location of a gasoline pump, reportedly removed from the Site in the 1960 s, was not able to be determined. No permits, spills, or leaks were reported for the Site by the county departments queried for information RECOGNIZED ENVIRONMENTAL CONDITIONS Cornerstone has performed a Phase I ESA in general conformance with the scope and limitations of ASTM E of assessor s parcel number known as 977 Danville Boulevard in. This assessment revealed the following Recognized Environmental Conditions 1 : 1 The presence or likely presence of hazardous substances or petroleum products on the Site: 1) due to significant release to the environment; 2) under conditions indicative of a significant release to the environment; or 3) under conditions that pose a material threat of a future significant release to the environment. Page 25

29 Laboratory analyses of soil samples detected OCPs, arsenic and lead exceeding residential screening levels. Removal of soil exceeding residential screening levels under regulatory oversight prior to Site development is recommended. In addition, chlordane exceeded its hazardous waste threshold in two samples, indicating that this soil may require special disposal considerations. A representative of the current owner reported, through the environmental questionnaire, the former presence of a gas pump on-site, but the location of this pump was not indicated. If the gas pump was associated with an above ground (AST) or underground fuel tank (UST), soil in the vicinity of the former tank and pump equipment may be impacted with petroleum hydrocarbons. No records were found to indicate the presence of a fuel tank or pump on the Site. The location of the former gas pump and any associated fuel tank(s) should be investigated further. This assessment identified no Controlled Recognized Environmental Conditions 2 or Historical Recognized Environmental Conditions 3 : As noted in ASTM E , the term Recognized Environmental Condition is not intended to include de minimis conditions that generally do not present a significant threat to human health or the environment and that generally would not be the subject of an enforcement action if brought to the attention of appropriate governmental agencies. SECTION 11: LIMITATIONS Cornerstone performed this Phase I ESA to support Dutra Estate Company, LP in evaluation of Recognized Environmental Conditions associated with the Site. Dutra Estate Company, LP understands that no Phase I ESA can wholly eliminate uncertainty regarding the potential for Recognized Environmental Conditions to be present at the Site. This Phase I ESA is intended to reduce, but not eliminate, uncertainty regarding the potential for Recognized Environmental Conditions. Dutra Estate Company, LP understands that the extent of information obtained is based on the reasonable limits of time and budgetary constraints. Findings, opinions, conclusions and recommendations presented in this report are based on readily available information, conditions readily observed at the time of the Site visit, and/or information readily identified by the interviews and/or the records review process. Phase I ESAs are inherently limited because findings are developed based on information obtained from a non-intrusive Site evaluation. Cornerstone does not accept liability for deficiencies, errors, or misstatements that have resulted from inaccuracies in the publicly available information or from interviews of persons knowledgeable of Site use. In addition, publicly available information and field observations often cannot affirm the presence of Recognized Environmental Conditions; there is a possibility that such conditions exist. If a greater degree of confidence is desired, soil, ground water, soil vapor and/or air samples should be collected by Cornerstone and analyzed 2 A Recognized Environmental Condition that has been addressed to the satisfaction of the applicable regulatory agency with hazardous substances or petroleum products allowed to remain in place subject to the implementation of required controls or restrictions. 3 A past Recognized Environmental Condition has been addressed to the satisfaction of the applicable regulatory agency or meeting of unrestricted use criteria established by the applicable regulatory agency without subjecting the Site to required controls or restrictions. Page 26

30 by a state-certified laboratory to establish a more reliable assessment of environmental conditions. Cornerstone acquired an environmental database of selected publicly available information for the general area of the Site. Cornerstone cannot verify the accuracy or completeness of the database report, nor is Cornerstone obligated to identify mistakes or insufficiencies in the information provided (ASTM E , Section 8.1.3). Due to inadequate address information, the environmental database may have mapped several facilities inaccurately or could not map the facilities. Releases from these facilities, if nearby, could impact the Site. Dutra Estate Company, LP may have provided Cornerstone environmental documents prepared by others. Dutra Estate Company, LP understands that Cornerstone reviewed and relied on the information presented in these reports and cannot be responsible for their accuracy. This report, an instrument of professional service, was prepared for the sole use of Dutra Estate Company, LP and may not be reproduced or distributed without written authorization from Cornerstone. It is valid for 180 days. An electronic transmission of this report may also have been issued. While Cornerstone has taken precautions to produce a complete and secure electronic transmission, please check the electronic transmission against the hard copy version for conformity. Cornerstone makes no warranty, expressed or implied, except that our services have been performed in accordance with the environmental principles generally accepted at this time and location. Page 27

31 Sample ID Date Depth (feet) Table 1. Analytical Results of Selected Soil Samples (Concentrations in mg/kg) Arsenic Lead Mercury 4,4 -DDD 4,4 -DDE 4,4 -DDT DDT Total alpha- Chlordane gamma- Chlordane Chlordane SS-1 (0-0.5) 9/5/ ½ < < < SS-2 (0-0.5) 9/5/ ½ <0.002 <0.002 <0.002 < <0.002 <0.002 SS-3 (0-0.5) 9/5/ ½ <0.002 <0.002 <0.039 <0.002 <0.002 SS-4 (0-0.5) 9/5/ ½ <0.002 <0.002 SS-5 (0-0.5) 9/5/ ½ <0.002 <0.002 <0.04 <0.002 <0.002 SS-6 (0-0.5) 9/5/ ½ < < SS-7 (0-0.5) 9/5/ ½ < SS-8 (0-0.5) 9/5/ ½ < < <0.02 <0.02 SS-9 (0-0.5) 9/5/ ½ < < SS-10 (0-0.5) 9/5/ ½ < <0.02 <0.02 Dieldrin Heptachlor epoxide Screening Level Criteria Basis NE NE 1.7 / BG 1 DTSC-SL 2 DTSC-SL 3 RSL 3 RSL 3 RSL 3 TTLC 4 NE NE RSL 3 / TTLC 4 RSL 3 RSL < NE BOLD Duverge, Establishing Background Arsenic in Soil of the Urbanized San Francisco Bay Region. DTSC - Recommended Screening Level (SL), HERO Note 3 - January 2016 Regional Screening Level (RSL), USEPA Region 9 - June Total Threshold Limit Concentration - California Code of Regualtions, Title 22. Not detected at or above laboratory reporting limit Not Established Concentration exceeds selected environmental screening criteria 977 Danville Blvd Data Tables Page 1

32 SITE N Vicinity Map Project Number Alamo, CA Figure Number Figure 1 Date Drawn By September 2017 RRN

33 Medlyn Lane Fourth Residence Main Residence SS-10 Third Residence Shipping containers SS-6 Site Plan SS-9 Garage SS-7 Second Residence and attached garage SS-2 SS-4 SS-3 SS-5 Iron Horse Regional T rail Sheds and Garage Danville Boulevard SS-8 Deodar Lane N Pangburn Lane Legend Approximate location of soil sample (SS) Base by Google Earth, dated 3/11/ APPROXIMATE SCALE (FEET) Alamo, CA SS-1 Drawn By September 2017 Date Figure Number Project Number Approximate Site Boundary Figure 2 RRN Camille Avenue

34 APPENDIX A TERMS AND CONDITIONS

35 APPENDIX B USER-PROVIDED INFORMATION

36 APPENDIX C DATABASE SEARCH REPORT

37 APPENDIX D HISTORIC AERIAL PHOTOGRAPHS AND TOPOGRAPHIC MAPS

38 APPENDIX E LOCAL STREET DIRECTORY SEARCH RESULTS

39 APPENDIX F RECORDS REVIEW DOCUMENTS

40 APPENDIX G OWNER QUESTIONNAIRE

41 APPENDIX H LABORATORY REPORTS