Major emergencies are a far greater risk for pesticide stores than they are elsewhere.
The primary objective in the design and
management of pesticide stores is to reduce the risk of fire.
Prevention is better than cure!
Pesticides, especially those formulated as liquids, present major fire hazards because the solvents used in formulations (oils and petroleum distillates) have low flashpoints and may be readily vaporized at normal temperatures. In poorly ventilated stores heavy vapours may accumulate near the floor if drums are left open or if leaks and spills are not cleared up. An electrical spark, naked flame or even the sun's rays concentrated by a glass container may cause an explosion followed by the spread of fire.
Some wettable powders are suspected of starting fires through spontaneous combustion, while sodium chlorate (used as a herbicide, defoliant, desiccant and soil sterilant) is a powerful oxidizing agent that easily catches fire and should only be supplied with a fire suppressant in the formulation (once sodium chlorate containers have been opened their entire contents should be used immediately).
The outside of pesticide stores should bear prominently displayed warning notices stating "Danger pesticides: authorized persons only" and "No smoking: no naked flame" as well as symbols. These rules should be strictly followed.
Fire extinguishers (powder or carbon dioxide, not water) should be available in the store and should be regularly checked. Static or running water (required, together with soap, for decontamination purposes anyway) should also be available and buckets of sand or earth (also required for absorbing any liquid pesticide spills or leaks) are useful for putting out small fires (Figure 28).
FIGURE 28 - Extinguishing a small fire in a pesticide store using shovefuls of sand or earth from a container
The local fire brigade should be informed of the
store's existence and the hazards involved. It is very useful to
place a notice on the outside of the store giving names and addresses
of those responsible for the store (including key holders) who can be
contacted in an emergency.
In the event of a fire it is essential to try to contain the pesticides that leak from burning and exploding containers in the store. Hence the need for bunding of some kind to be provided when the store is built; bunds also prevent the water used to fight the fire, which inevitably becomes contaminated with pesticides, from contaminating the neighbourhood and thus the environment generally.
Contamination of the environment from combustion products such as smoke and fumes cannot be prevented. A light roof designed to collapse easily in a fire will at least permit the fumes to be carried upwards away from the fire-fighters (Figure 29).
FIGURE 29 - Pesticide store in flames - the light roof has collapsed thus preventing an explosion
Fires in pesticide stores that contain
organophosphorus compounds and carbamates can be extremely dangerous
to fire-fighters, who should never go downwind of the fire and should
always wear breathing apparatus.
Solid water streams from fire-fighting hoses should be avoided since they can disperse the pesticide, especially powder formulations, over a wide area. Care should also be taken to avoid dragging fire hoses through contaminated water.
Protective clothing and equipment used by fire-fighters should be thoroughly decontaminated after the fire.
Flooding during seasonal rains is a common event
in tropical countries. Flooded pesticide stores are subject to
Cardboard or paper containers in which many pesticides are packed lose strength and may leak or burst open when wet. Other containers, especially partially empty drums of liquid, may be swept away with a flood. Environmental contamination over a wide area may result from either of these events; water supplies may become polluted and pesticide containers may present a hazard to people who find them.
Dangers from fire, flooding and destruction during civil disturbances emphasize the value of keeping records of stocks in a place where they will be safe in an emergency. Records of the quantities and types of pesticide involved prove invaluable in subsequent efforts to clean up, trace missing containers and assess the environmental risk and financial loss caused by the emergency.