(CNN) Generally, tortilla chips don't heat up until you put salsa on them.

But in Austin, Texas, the fire department had to put out fires out not one, but four times caused by the spontaneous combustion of tortilla chips.

It started when a tortilla chip factory was testing a new way to handle its chip waste. The company crushed the chips into a fine, powder-like substance and put the powder into boxes that had soaked up oil, Austin Fire Department division chief Palm Buck told CNN.

When the weather heated up, the chip dust heated up too -- and burst into flames.

"Certainly tortilla chips was a new thing for us," Buck said.

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