Addl Methane Study Needed - Terry Park CommUNITY

The subject property is planned to be redeveloped and the City of Huntington Beach requested the following items be completed prior to rough or precise grading plan approval. Due to the site history and the proximity of oil wells (less than 500 feet), this project will need to show compliance with CitySpecification #429, soil gas testing for methane gas is required. According to California Department of Conservation (DOC), Geologic Energy Management Division (CalGEM) Southern District, no oil orgas wells are located on the subject property; however, the subject property is located within the Huntington Beach Oil Field. The closest oil well to the subject property, API 0405901826/HKR #1, is located approximately 430 feet to the east of the subject property. A methane sample plan shall be submitted to the City of Huntington Beach Fire Department for review and approval, prior to the commencement of sampling.

If methane gas is discovered in the soil, the following City Specification would be applicable and the grading, building, and methane plans must reference that the corresponding methane mitigation features will be installed. These can include a sub-slab methane barrier and vent system per City Specification # 429, Methane District Building Permit Requirements prior to plan approval. Additional passive or active methane mitigation measures may be required by the fire department based on the concentrations of methane vapor documented during soil sampling.

Partner completed a Phase II Subsurface Investigation Report (Phase II) for the subject property, dated July18, 2023, on behalf of Kelemen Company, to evaluate the potential impact of petroleum hydrocarbons,VOCs, PCBs, polycyclic aromatic hydrocarbons (PAHs), herbicides, metals, methane, and/or hydrogen sulfide (H₂S) to soil and/or soil gas as a consequence of a release or releases from the on-site operation sand oil production activities in the subject property vicinity.

The scope of the Phase II included 15 soil borings. Fifteen soil samples were analyzed for carbon chain total petroleum hydrocarbons (TPH-cc) andVOCs; six soil samples were analyzed for metals; two soil samples were analyzed for PAHs, PCBs, and chlorinated herbicides; 15 soil gas samples were analyzed for VOCs; and 33 soil gas probes were field screened for methane and H₂S.