On Thursday night mc911 was advised of an old abandon bus fire on Rt.46 by BLS 39-70 while returning from earlier call. 39-4 advised fully involved bus fire with possible haz-mat. Engine 39 responded with 5, tanker 39 with 2, brush 39 with 2, tanker 33 with 2, BLS 39-70 on scene with 2. 39-4 assumed command and advised engine 39 to remain at distance due to possible haz-mat. Upon arrival engine 39 approached with caution when multiple explosions occurred sending fire into woods and projectiles into strutures beside engine. Explosions were reported to 911 center from residences over 3 miles away. Engine 39 back off further and attacked fire with deck gun. Tanker 39 and tanker 33 supplied engine until fire knocked down. Personnel approached with much caution to extinguish brush fire and remaining fire at bus. Explosions found to be from small disposable propane cylinders. Total of 3 found. Also found inside of bus were oxygen and acetylene torches(large bottles). Units remained on scene for 2 hours.