Final answer:
Division 1.3 of explosive hazard class 1 contains items that produce fires which are difficult to extinguish due to their intense flames and significant radiant heat.
Step-by-step explanation:
The division of explosive hazard class 1 that contains items that produce fires that burn vigorously and are difficult to put out is known as 1.3. This division specifically includes substances and articles that have a fire hazard and either a minor blast hazard or a minor projectile hazard or both, but not a mass explosion hazard. Such substances are capable of creating a considerable radiant heat or that burn with an intense flame and that may be used to produce pyrotechnic effects. In the event of ignition during transport, handling, or storage, materials in this division may pose significant dangers due to the intensity of the fire and the difficulty to extinguish it.