Propane would have two hazard symbols - the one for a compressed gas and another to show that it is a flammable material. Reactive flammable materials are those which may suddenly start burning when it touches air or water, or may react with air or water to make a flammable gas. The material may be a solid, liquid or gas which makes up the different divisions that fall under this class. The symbol for this class is a flame with a line under it inside a circle. Oxygen is necessary for a fire to occur.
Some chemicals can cause other materials to burn by supplying oxygen.
They can have strong reactions which can result in an explosion. Class D materials are those which can cause harm to your body. They are divided into three major divisions. These are materials that are very poisonous and immediately dangerous to life and health. Serious health effects such as burns, loss of consciousness, coma or death within just minutes or hours after exposure are grouped in this category.