| Landfill fires can occur even in modern and well | | | | Landfill fires can be prevented and minimised if |
| run landfills, although with good monitoring and site | | | | they begin, when they are still no more than hot |
| controls they are seldom more than a nuisance. | | | | spots in the waste. They cannot occur unless |
| However, they are especially dangerous as they | | | | oxygen levels rise in the landfill. Therefore, action |
| can emit dangerous fumes from the combustion | | | | trigger limits for oxygen and methane should be |
| of the wide range of materials contained within | | | | established as part of the process safety control |
| the landfill. | | | | system and managed by regular monitoring. In |
| Since in most cases the supply of air is likely to | | | | some circumstances this might require alarmed |
| be small, the rate of combustion inevitably will be | | | | continual monitoring of critical parts of the landfill |
| slow. There are a number of possible sources of | | | | gas field. |
| ignition. These can include ignition sources buried | | | | If a fire does take place the effectiveness of the |
| within the deposit of waste materials, the deposit | | | | fire-fighting measures should be assessed by |
| of pyrophoric materials (for example, finely | | | | long-term monitoring of temperature and carbon |
| divided metal turnings can initiate ignition, fires lit | | | | monoxide concentrations. |
| on the surface of a site, or self-heating and | | | | Landfill fires are usually best be extinguished by |
| ignition). Oxidising agents which may be present in | | | | smothering with soil, using heavy equipment and a |
| some wastes which could also provide sufficient | | | | suppressant agent, or simply temporarily shutting |
| oxygen to initiate spontaneous combustion. | | | | down the gas extraction system. No one method |
| A fire hazard can exist by virtue of the presence | | | | will work for all conditions. |
| of uncompacted combustible waste materials in | | | | Subsurface landfill fires also, unlike a typical fire, |
| the landfill, the voids in which can provide sufficient | | | | cannot be put out easily with water. Very large |
| air to support combustion underground. Since the | | | | quantities are needed if any success is likely and it |
| supply of air is likely to be small, the rate of | | | | is very hard to get the water to the seat of the |
| combustion inevitably will be slow. | | | | fire before it drains away through the rest of the |
| Landfill fires often involve PVC due to the fact | | | | surrounding waste. |
| that there is commonly PVC present in all | | | | There is no doubt that landfill fires are a serious |
| domestic and commercial waste. This makes | | | | matter to operators and managers. They can |
| landfill fires a further source of dioxin. Dioxin builds | | | | cause incredible damage, and create a significant |
| up in the environment around the point at which it | | | | hazard to staff, the local community and the |
| is emitted making it of concern when it is | | | | environment. Staff on the landfill can be at risk if |
| generated over a long period. | | | | the landfill subsides and the surface becomes |
| Dioxins are even often found in hazardous | | | | unstable above the fire. |
| concentrations in the tissues of animals and | | | | Because landfill fires usually burn slowly and deep |
| humans living thousands of miles away from | | | | within the waste, there is not normally any visual |
| industrial sources, such as whales and polar bears | | | | sign such as smoke. However, knowing where, |
| and have been seen in Inuit mother's breast milk. | | | | how many and the extent of underground fires, is |
| It is a fact that dioxin compounds are never | | | | essential to those in charge of containing and/or |
| manufactured intentionally but are produced | | | | extinguishing them once they have started. |
| accidentally whenever chlorine gas is used or | | | | Infra-red surveys flown at height above the landfill |
| chlorine-based organic chemicals are burned or | | | | can be useful to plot the extent of the fire in |
| processed under reactive conditions. | | | | addition to monitoring the gas composition inside |
| Dioxin emissions from PVC combustion are not | | | | landfills. |
| limited to landfill fires of course, and also occur | | | | So, landfill fires are perhaps some of the most |
| regularly due to the estimated 1 million annual fires | | | | difficult fires of them all to fight because they are |
| that burn buildings and vehicles, as these are two | | | | frequently deep beneath tons of debris or other |
| sectors that use substantial amounts of PVC. | | | | such materials. Dioxins which are very toxic to life |
| Landfill fires can also be fuelled by methane gas in | | | | are an additional worry from landfill fires are |
| the landfill of course and by every combustible | | | | another potential source, because landfill also |
| element of waste especially by by wood and | | | | contains waste PVC. |
| paper debris. | | | | |