Specifications include, but are not limited to: Annual Environmental Monitoring and Reporting. 1. Continuous remote, electronic monitoring of three (3) SSDS extraction fans to ensure continuous operation; 2. Quarterly inspections and monitoring (air velocity and vacuum) of the three (3) rooftop fans to verify proper operation and effluent concentrations using a photoionization detector with part-per-billion sensitivity as well as rooftop fan effluent sampling and analysis for VOCs via USEPA Method TO-15; 3. Quarterly inspections of the indoor methane monitoring system (eight (8) locations); 4. Monthly sub-slab monitoring of vacuum pressure and vapor-phase constituents (VOCs via USEPA Method TO-15 and methane) at eleven (11) locations to confirm that a negative pressure exists beneath the building slab due to continuous fan operation; 5. Monthly sub-slab vapor sampling of eleven (11) locations (six (6) collected at a time on a rotating schedule) and analyzed for methane and volatile organic compounds (VOCs) via USEPA method TO-15 as well as evaluation for potential VOC rebound effect.