GEOTECHNICAL | ENVIRONMENTAL | MATERIALS
January 26, 2023
Project No. 3865-SD
Las Posas, LLC
c/o Avenue Secured Capital Group
2555 Locust Street
San Diego, CA 92106
Subject: Due Diligence Environmental Review
A Portion of Assessor’s Parcel Number (APN) 219-16 2-57-00 225 North Las Posas Road
San Marcos, California
References: See Page 7
Dear Mr. Tate:
In accordance with your request, GeoTek, Inc. (GeoT ek) has prepared this Due Diligence Environmental Review for the subject project. The general review and review comments are based on review of the referenced reports prepared by Terracon (2019) and Stantec (2021) and GeoTek’s experience in the vicinity and with this type of project.
Site Description and Proposed Development
The site is the eastern portion of Assessor’s Parce l Number (APN) 219-162-57-00, which is located and addressed as 225 North Las Posas Road, in the City of San Marcos, San Diego County, California, see figure 1 (Site Location Map ). The Site Location Map differentiates the site vs the legal address of 225 North Las Posas Ro ad. This environmental due diligence is focused only on the site and not entirety of 225 North Las Posas Road.
The site is currently vacant land. The site is bou nded by a railroad easement to the north, by a multifamily residential property to the east, by Ar morlite Drive to the south, and George’s Burgers Restaurant (217 North Las Posas Road) and A T&T facility (225 North Las Posas Road) to the west. In the immediate vicinity of the site, West Mission Road, followed by a Chevron gas station (1290 West Mission Road) and Palomar Com munity College (1140 West Mission Road) are located to the northeast; a vacant lot and Palomar Station apartments complex (1257 Armorlite Drive) are located to the south beyond Ar morlite Drive; and Palomar Station apartments complex (1250 Armorlite Drive) is located to the southeast.
Las Posas, LLC Page 2
Due Diligence Environmental Review Project No. 3865-SD
San Marcos, San Diego County, California January 26, 2023
GeoTek anticipates that the proposed development wi ll consist of four levels of wood-framed apartment homes above a concrete podium consisting of vehicular parking and commercial space. The first level is anticipated to be at gra de with Armolite Drive and AT&T parking lot.
Although grading plans have not been provided, GeoT ek anticipates that cuts and fills of up to approximately 13 to 19 feet may be needed (not incl uding remedial grading) to bring the site to design grades
Geologic/Geotechnical Conditions
The site is located in an area geologically mapped by Kennedy (2008) to be underlain by tonalite (Kennedy, M.P.; and Tan, S.S., 2008). Geotechnical conditions on a due diligence level (desktop reconnaissance) was performed by GeoTek concurrentl y and separate to this environmental due diligence.
Report Review
Phase I Environmental Site Assessment (Terracon, 2019)
Terracon issued a Phase I Environmental Site Assessment report for the subject parcel dated May 10, 2019. It should be noted that Terracon’s Phase I report included the entirety of 225 N. Los Posas and did not differentiate between the site an d the portion of the property being retained by AT&T.
Terracon provided a summary of the findings, and these are repeated below:
Site Reconnaissance
During the site reconnaissance, Terracon reported t hat one emergency generator, one natural gas generator, one portable stand generator and an associated 200-gallon diesel belly tank (aboveground), two 120-ton chiller units, one unman ned telecommunications shelter, three 5-gallong containers, safety data sheets, interior floor drains, one pad mounted transformer and one solid-waste dumpster were observed.
Terracon reported that Recognized Environmental Con cerns (RECs) were not identified with the abovementioned features. Additionally, one 5,0 00 gallon diesel UST was identified on the north side of the site building. This UST is furth er discussed in the Records Review section of this report.
Based on Terracon’s review of the adjoining propert ies, Terracon stated that no RECs were observed.
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Due Diligence Environmental Review Project No. 3865-SD
San Marcos, San Diego County, California January 26, 2023
Historical Information
Based on review of historical information, the lega l lot consisted of undeveloped and/or vacant land from as early as 1893 through the mid-1960’s, when a commercial building and associated ancillary building were built on the west portions of the property. By the late 1970’s, the central ancillary building was cleared, and the com mercial building underwent successive expansions in the late 1970s and the mid-1990s. Pr ior occupants included Western Electric, Pacific Bell and Direct TV.
Records Review
Selected federal and state environmental regulatory databases, as well as, responses from state and local regulatory agencies were reviewed. The l egal lot was identified in the regulatory database. AT&T California, Pacific Bell and Verizo n Wireless (225 North Las Posas Road) was listed with the following databases:
FINDS (Facility Index System/Facility Registry System) ECHO (Enforcement & Compliance History Information)
HAZNET (Facility and Manifest Data)
RCRA-SQG (Resource Conservation and Recovery Act – Small Quantity Generator) UST (Underground Storage Tank)
HIST UST (Hazardous Substance Storage Container Database) SWEEPS (Statewide Environmental Evaluation and Planning System) San Diego County HMMD (San Diego County Hazardous Materials Division)
Based on review of the RCRA and HAZNET listing, Pac ific Bell was permitted as a large quantity generator of hazardous waste in 1981 and a small quantity generator of hazardous waste in 1996 with no violations reported. Wastes g enerated included aqueous solutions with total organic residue less than 10%, unspecified aq ueous solution, waste oil, mixed oil and unspecified oil-containing waste between the years 1994 and 2015.
Based on a review of the FIND and ECHO databases, violations were not reported.
Based on review of records from the San Diego Count y Department of Environmental Health (SDCDEH), three (3) diesel containing UST’s (one 55 0 gallon, one 1,000 gallon and one 5,000 gallon) were identified on the site. The location and status of the 550-gallon UST was reported to be unknown. The 1,000 gallon UST was reported t o have been removed in 1994, with a soil assessment completed and closure from SDCDEH. The 5,000 gallon tank was reported to still be in existence and was installed in 1994, with upg rades to the piping and sump performed in 1998. The 5,000 gallon tank was observed in Terracon’s site reconnaissance.
Terracon concluded the report with the following RECs:
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Due Diligence Environmental Review Project No. 3865-SD
San Marcos, San Diego County, California January 26, 2023
The absence of information regarding the location o f and status of the 550 gallon diesel UST represents a significant data gap to the site a nd an REC. Further investigation should be performed.
Although the provided tank gauging, pressure test records and state compliance records suggest that leaks have not been recently identifie d or reported for the 5,000 gallon UST, in Terracon’s experience, regardless of contro ls, UST system leaks commonly occur and sometimes they occur below the leak level detection rate limit. Based on the duration of operations associated with the 5,000 gallon UST (1995 through present) and absence of a subsurface investigation, the existing 5,000 gallon UST represents a REC to the site.
Terracon further reported that the remaining facili ties listed in the database report do not appear to represent RECs to the site at this time b ased upon regulatory status, apparent topographic gradient and/or distance from the site.
Phase II Environmental Site Assessment (Stantec, 2021)
Stantec issued a Phase II Environmental Site Assessment report for the subject project (i.e., a portion of APN 219-162-57-00) on March 23, 2021.
Stantec reported that the following identified RECs were identified in connection with the subject project in a Phase I ESA prepared in March 2021. (Note: GeoTek was not provided with the Phase I ESA report prepared by Stantec for this review.)
A 550-gallon UST was reportedly installed at the pr oject site in the northwestern portion of the site in 1972. No leaks or spills ha ve been reported for the site; however, the presence of the UST constitutes a REC for the s ite. Stantec recommended performing a ground penetrating radar (GPR) survey to verify if the UST remains on the site. In addition, Stantec recommended that a soil and soil vapor assessment be completed at the UST location to evaluate the subsurface conditions beneath the site.
Railroad spurs are located adjacent to the north of the site. Herbicides are commonly applied to railroad alignments and heavy metals ass ociated with herbicidal application are commonly found in these areas. Due to the pres ence of the spurs, Stantec recommended performing a Phase II subsurface invest igation to sample and analyze shallow soil samples along the site property bounda ry nearest the rail line for the presence of heavy metals. The need for sampling fo r these compounds given the intended use is for protection of construction work ers during development of the paths when exposed to dust. The second issue is the pote ntial for off-site removal of soils, which will require profiling by chemical analysis t o determine the proper location for disposal.
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Due Diligence Environmental Review Project No. 3865-SD
San Marcos, San Diego County, California January 26, 2023
In order to address the above noted RECs, Stantec o versaw a ground penetrating radar (GPR) survey performed on February 22, 2021 by GPRS, a ut ility subcontractor, to locate any suspected UST or UST-related piping or other anomal ies remaining on the site. The scope of work was reported to consist of scanning an area me asuring 15 feet by 30 feet in the northwestern portion of the site. An anomaly which may be a potential UST was detected at approximately two to four feet in depth in the area scanned.
Stantec reported that the GPR survey identified an anomaly which may be the 550-gallon UST in the northwest portion of the site at approximate ly two to four feet in depth. Stantec recommended removing and disposing of the UST in accordance with all applicable laws.
Additionally, Stantec advanced four soil borings in the western perimeter on March 1, 2021.
Two of the borings were reported to have encountere d refusal at approximately two feet below the ground surface (bgs) and were abandoned. Soil samples were collected from two locations along the northern perimeter at one-, two - and three-feet bgs to evaluate the adjacent railroad tracks and were submitted for ana lysis of organochlorine pesticides (OCPs), lead and arsenic. The deeper samples (two- and thr ee-feet bgs) were placed on hold pending analysis of the shallow soil samples. The two rema ining soil borings were advanced in the vicinity of the anomaly on the northwestern corner of the site. Due to difficult drilling conditions, the soils vapor probe for one of the bo rings was set at 3.5-feet bgs and the probe for the second boring was set at 4-feet bgs.
The results of the soil samples collected along the northern property line near the rail line were reported to be “non-detect” for arsenic and OC Ps with the exception of a minor detection of heptachlor at 0.0014 mg/kg, which is w ell below screening levels for residential use. Lead was reported to have been detected at 4. 8 and 7.2 mg/kg in two (2) of the samples (S-1 and S-2), Stantec reported that because all d etected metal concentrations are within typical California naturally-occurring background c oncentration ranges and do not exceed Department of Toxic Substance Control (DTSC) Hero N ote 3 or Environmental Protection Agency (EPA) Regional Screening Levels (RSLs) for r esidential use, the adjacent railroad tracks do not represent a REC to the site and nor further assessment appears warranted.
Total Petroleum Hydrocarbons (TPH) as vapor and various volatile organic compounds (VOCs) were detected at low concentrations in the soil vap or borings. These concentrations were reported to all be below the most conservative scre ening level between the USEPA Region 9 RSLs and DTSC Hero Note 3 with an attenuation facto r of 0.03, with the exception of benzene. Benzene was reported to be detected at 5. 7 micrograms per cubic meter (µg/m 3) in
one of the soil vapor borings (SV-2) which is above the RSL with an attenuation factor of 0.03, but below the RSL with an attenuation factor of 0.0 01. Given the concentration was only slightly above the RSL with an attenuation factor of 0.03 (which is not the official screening level and which has not been adopted by any state agency) , and well below the risk-based screening level of 97 µg/m 3, this single detection is considered a de minimis condition and no further assessment appears warranted for soil vapor.
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Due Diligence Environmental Review Project No. 3865-SD
San Marcos, San Diego County, California January 26, 2023
Summary of Environmental Conclusion Presented by Others
The 550-gallon UST, the 5,000-gallon UST, and railroad spur were presented as REC’s by either Terracon or Stantec or both. The phase II investig ation by Stantec concluded the 5,000-gallon UST and railroad was no longer an REC. However, Sta ntec’s hypothesized location of the 550- gallon UST should be further evaluated.
Environmental Site Reconnaissance and Discussion
On December 14, 2022, Hal Hays Construction, Inc. w as contracted by others (property owner of 225 N. Las Posas Road), to evaluate the an omaly identified by Stantec’s Phase II investigation. The excavation was performed with a conventional rubber-tired backhoe with a 24-inch wide, smooth edge, bucket. The excavation was approximately six feet long and three feet wide. Shallow refusal by granitic rock (Tonalite) was encountered at an approximate depth of two to three feet below grade. A weathered core stone was encountered at the approximate location of the anomaly identified in Stantec’s Phase II investigation. A second core stone was encountered approximately six feet north of the recorded anomaly. To further evaluate a potential UST, the excavation was length ened to the north and south for a total linear excavation length of approximately twelve feet. North and south of the excavation, core- stones extruded from the subsurface. The excavatio n encountered a thin layer of topsoil over weathered Tonalite and encountered non-rippable roc k at a depth three feet, but became as shallow as one foot above the core-stones.
Based on GeoTek’s review of Stantec’s Phase II investigation, no identifiable logic was presented supporting Stantec’s hypothesized 550-gallon UST location, other than the anomaly identified by the GPR survey.
To further evaluate the possibility of the 550-gall on UST tank existing on site, the following discussion is provided.
The permitting of the tank occurred in 1972.
Between 1967 and 1998, there was no visible earth d isturbances on portions of the site where Stantec located the potential UST location.
Between 1954 and 1963 earth can be indirectly assum ed to be exposed in the central portion of the site. By 1964, some vegetation can be observed in sporadic areas of the site. Undocumented fill was identified in the cent ral portion of the site. It is reasonable to assume the earth shown in the 1964 arial image w as from spoils generated from the construction of the buildings and cut pads west of the site. Between 1999 and 2003, the site underwent minor gra ding as noted by scrubbed brush along the western portion of the site, but this is well outside the year of when the 550 gallon UST tank was permitted.
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Due Diligence Environmental Review Project No. 3865-SD
San Marcos, San Diego County, California January 26, 2023
The site was not developed until sometime between t he years of 2003 and 2005, this was 30 years after the UST was installed. The port ions of the site developed was limited to the western boundary by construction of outside storage area, parking lot, and a trash bin enclosure.
The natural vegetation is slow growing and a scar f rom an excavation would likely be present in historic photos or satellite imagery, or a noticeable lack of chaparral bushes.
A scare was not observed, the area lacking chaparra l brush is the area identified by Stantec to be a potential UST location.
Conclusion
Evidence is not present to conclude the 550-gallon UST is present on the site.
If the UST
remains on the portion of property to be retained b y AT&T, the UST does not pose a recognized environmental concern to the site. The UST, if it still exists, is potentially located in the northwest or southeast vicinity and adjacent to the existing AT&T building. These possible locations would locate the UST at an elevation lowe r or cross gradient to the proposed elevations relative to the site.
The site is underlain predominately by granitic bed rock that exhibits low permeability and reduces the likelihood of volatile organic compound s (gasses from a leaking petroleum tank) as well as fluids potentially impacting the site. The soil-gas vapor evaluation performed by Stantec suggests that an offsite 550-gallon UST tank has not impacted the site.
Based on the existing reports by Terracon and Stant ec, as well as, the subsurface exploration performed on December 14, 2022, the RECs identified by Stantec, in GeoTek’s professional opinion, does not pose an REC to the site.
GeoTek concurs with Stantec’s conclusions regarding the soil-gas vapor study and the railroad alignment adjacent to the site.
GeoTek recommends no further environmental investigation is necessary.
Las Posas, LLC Page 8
Due Diligence Environmental Review Project No. 3865-SD
San Marcos, San Diego County, California January 26, 2023
LIMITATIONS
The comments are professional opinions that are lim ited to the extent of the available data.
These opinions have been derived in accordance with current City/County/State standards of practice and no warranty is expressed or implied. Standards of practice are subject to change with time.
Respectfully submitted,
GeoTek, Inc.
Christopher D. Livesey Anna M. Scott
CEG 2733, Exp. 05/31/23 Project Geologist
Vice President
Distribution: (1) Addressee via email
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Due Diligence Environmental Review Project No. 3865-SD
San Marcos, San Diego County, California January 26, 2023
REFERENCES
Kennedy, M.P., Tan, S.S., Bovard, K.R., Alvarez, R. M., Watson, M.J. and Gutierrez, C.I., 2007, “Geologic Map of the Oceanside 30x60-Minute Quadran gle, California,” California Geological Survey, Regional Geological Map RGM-2, scale 1:100,000.
Stantec, 2021, “Phase II Environmental Site Assessm ent, 225 North Las Posas Road, San Marcos, California 92069,” Project No.: 185805035, dated March 23.
Terracon, 2019, “Phase I Environmental Site Assessm ent, AT&T: San Marcos, 225 North Las Posas Road, San Marcos, San Diego County, Californi a,” Terracon Project No. 60197159, dated May 10.