see also Class A Foam
Fire Retardant
Fire retardant is a substance used by the Department of Sustainability and Environment to assist in the control of bushfires in Victoria. The retardant contains chemicals that are generally found in a broad range of agricultural fertilisers and it is applied by dropping from fixed wing aircraft or occasionally from a helicopter with a fixed tank.
Retardant is used to contain fires when access by ground crews is difficult or unsafe, or when there will be a delay in crews arriving at the fire.
Retardant is normally purchased from suppliers as a dry powder, and it is mixed with water, using specially designed equipment, to form a slurry of a similar consistency to tomato sauce.
Fire retardant fact sheet (PDF - 306 KB)
 Loading Dromader firebomber with retardant | The retardant slurry is laid as a barrier in front of the fire. As the fire burns into the fuel coated with retardant, a chemical reaction occurs, which effectively makes the fuel unavailable to the fire. The water in retardant is used only as a carrier - retardant is still effective even when the water has evaporated. All retardants used by DSE are rigorously tested for environmental effects and health effects by the United States Department of Agriculture (USDA). Only retardant approved by the USDA is used in Victoria. |
 | The retardant currently used by DSE is a proprietary product manufactured by Solutia (previously Monsanto), and known as ‘Phos-chek D75R’. The principal component of retardant is Diammonium Sulphate. D75R also includes some Diammonium Phosphate and Monoammonium Phosphate, a natural gum thickener, small amounts of colouring agent (iron oxide), and preservative. Although retardant is considered non-toxic and is used only in strategic locations and in small quantities, it can have short term localised adverse affects on aquatic life in streams. Obviously it is good practice to minimise the amount of any extraneous material that may enter the environment, especially water courses. Accordingly DSE adopts standard practices which minimise the possibility of retardant entering streams - for example by dropping retardant along ridge lines, where practicable, and where it is generally most effective in assisting in the control of a fire. |