Preventing Landfill Fires
Considering the sheer volume and countless variety of materials entering the landfill, the potential for fires shouldn't come as a big surprise. Fortunately, staff at the landfill work diligently to identify hazardous conditions in their efforts to prevent or respond to above ground and subsurface fires.
Above ground fires are the most common fire and typically result from smoldering materials brought into the landfill. Burn barrels filled with ash are one of the most common causes as they often appear to be extinguished. However, when emptied and air is introduced to the lower parts of the barrel, the materials can rekindle. Unspent fireworks are another common material to watch for along with photo sensitive materials that can ignite when exposed to sunlight. In addition to treatment requirements imposed on local businesses, landfill staff take precautions to keep photo sensitive materials off machinery and get the materials covered quickly to avoid potential sun exposure. Identification of materials is a key part of surface fire prevention. Above ground fires are the easiest to fight as they are easily seen and can usually be extinguished with water or more commonly smothered with dirt.
Subsurface fires are not so easily detected or fought. These fires usually start from spontaneous combustion and can start well below the surface. One factor which can start a subsurface fire is over drawing on the gas wells which will introduce excess oxygen into the fill and cause the decomposition process to generate excess heat to the point of ignition. These fires are not generally visible and will smolder for long periods of time with no open flame. Some of the signs of a subsurface fire are excess temperatures at the gas wells (+140 degrees F) and areas which suddenly show settlement on the surface. Subsurface fires require a different approach for fighting as opposed to surface fires. Water isn’t preferred as it would require large amounts of water and causes issues such as increased leachate production and possible slope instability. Sometimes, excavation of subsurface landfill fires is the only way to guarantee the fire has been extinguished. These fires can burn for weeks, months, or even years if not stopped.
Landfill operators are always watching for materials being brought in which could potentially start a fire. Residents and haulers are encouraged to take proper steps to ensure materials are easily identified and any ash or fire debris is fully extinguished prior to disposal at the landfill.
