Getty Images, photo by Quim Llenas

Scratch and sniff cards come in many forms, from perfume to cologne and natural gas. Energy West in Great Falls, Montana, passed out natural gas cards to their customers that have an artificial smell of gas when you scratched them. The idea was to have residents notice the smell in case of  a leak and they seem to work all too well.

Workers at the company recently discarded several boxes of the scratch and sniff cards because they had expired, but when the garbage truck picked them up and compressed them it was the same as if all the cards in the boxes had been scratched at the same time causing a panic in the area. The odor caused numerous false alarms and buildings were evacuated because the smell traveled through downtown.