TRUE or FALSE: The presence of the rainbow effect at a fire scene is a reliable indicator of an ignitable liquid being present.

The assertion that the presence of the rainbow effect at a fire scene is a reliable indicator of an ignitable liquid being present is false. The rainbow effect typically refers to the visual phenomenon observed when a thin layer of oil or ignitable liquid floats on water. While the presence of a rainbow sheen can suggest that a flammable liquid may have been present, it is not a definitive indicator.

Conditions such as weather, the nature of the materials involved in the fire, and the composition of the liquid can greatly affect the appearance of this sheen. Additionally, other substances such as non-flammable oils or other contaminants can produce similar effects, making it unreliable for concluding the presence of an ignitable liquid. Therefore, while the rainbow effect should be noted and investigated further, it cannot be solely relied upon for confirming ignitable liquid at a fire scene.