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FORWARD LANDFILL NON-WATER CORRECTIVE ACTION PLAN 4.3 FIRE IMPACTS 4.3.1 Subsurface Fires Subsurface landfill fires are most commonly caused by the intrusion of oxygen into the refuse prism from overdrawing of the gas collection system, which increases aerobic decomposition, resulting in the generation of methane and increased temperatures. This can cause ignition of the methane gas resulting in a fire. This underground combustion/oxide can cause damage to the landfill gas collection systems and potentially the intermediate and final cover. The existing JTD for the Forward Landfill contains provisions to prevent, monitor, and remediate subsurface fires. In addition, Republic Services, Inc., the parent company of Forward, Inc., has a standard operating procedure for managing landfill gas collection systems. Forward Landfill also has a protocol which sets forth procedures for the intermittent operation of landfill gas extraction wells in low-methane producing areas of the landfill to protect against underground combustion or oxidation events. This protocol has been established to mitigate some previous occurrences. This protocol is intended to ensure wells operating at an oxidization level above 5 percent are not causing a subsurface oxidation event. The JTD includes a Health and Safety Plan, which includes a Fire Prevention Plan component. Based on the CalRecycle document on BMPs, "A landfill's ® joint technical document and/or postclosure maintenance plan may contain provisions to prevent, monitor, and remediate subsurface fires. If not, subsurface fires should be addressed in the CA Plan." Therefore, this Corrective Action(CA) need not address subsurface fires. 4.3.2 Wildfires Wildfires have been documented to destroy or damage landfill gas collection and monitoring systems, vegetation and irrigation systems, damage to these systems can affect the integrity of the cover, drainage systems, and conveyance systems. The potential damage is dependent on such things as whether the gas collection and conveyance systems are buried to protect them from fires, and whether other protective measures, such as adequate fire breaks, are provided. The potential damage to a landfill caused by wildfires can vary significantly depending on the facility location, surrounding terrain, and local weather conditions. CalRecycle's BMP guidelines recognize the Department of Forestry and Fire Protection (Cal Fire) and local fire agencies for potential fire hazards. The causal effect is outlined in the background documentation for BMPs required. Landfills located within or adjacent to hazardous zones, moderate/medium or high/very high, should be evaluated for potential damage. In researching the fire hazard zone for the Forward Landfill, Cal Fire's maps for the San Joaquin . County fire hazard is the responsibility of the local fire jurisdiction. This means that the site is M:\2011-012"WFnaeroar.uocx 16 Geo-Logic Associates