The answer is: highly flammable.
The Material Safety Data Sheet (MSDS) is a detailed fact sheet summarizing information about a chemical's hazardous ingredients.
Balanced chemical reaction of propane combustion:
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O.
This is very exothermic reaction.
Chemical formula for propane is CH₃-CH₂-CH₃.
Propane is a three carbon alkane (acyclic saturated hydrocarbon).