can piles of hay start on fire by spontaneous combustion
It is not uncommon for a fire to occur when transporting hay, like the fire July 18 in Helena. Such fires are most likely started by overheated exhaust pipes or a thoughtless passerby throwing a cigarette out a car window. However, hay fires on farms are much more likely to be caused by spontaneous combustion. Such fires damage or destroy buildings and equipment in addition to the hay consumed. In 1998, the Montana Fire Marshall's office recorded 148 agricultural product fires that resulted in one injury and over $797,000 of damage.