Security concerns with regard to vending machines usually revolve around prevention of theft measures. A can vending machine might be designed to have strength similar to a modern safe. As a result, any vending machine can be very heavy. A study found that a small number of people are killed or seriously injure every year when vending machines topple over on them. This could happen either while trying to steal from them, or venting frustration on them, especially when a malfunction causes the machine to fail to dispense the purchased item or the proper change. The vending machines themselves, being large and heavy, are difficult to steal without drawing attention.
As far back as 1988 an article in the Journal of the American Medical Association documented 15 cases in which men trying to get a can out of the can vending machine were crushed. Three died, the other 12 required hospitalization for injuries such as fractures of the skull, toe, ankle, tibia, femur, and pelvis; intra-cerebral bleeding; knee contusion; and one punctured bladder. The article stated that because the soft drinks were located in the upper half of the machine (to enable their falling into the dispensing slot), the center of gravity of the vending machine was abnormally high. This created a risk of the machine falling if it tipped only 20 degrees, a deceptively small angle. Given that a large, fully loaded soft drink machine can weigh over 880 lbs (400 kg), the chances of anyone surviving it should a vending machine falling on them are very slim.
In order to prevent injuries or death from tipping or striking the machine, most modern can vending machines are equipped with spirals to hold products contain lasers near the access door at the bottom. If a purchased item does not break the laser beam when falling, the spirals will automatically turn, usually three times to ensure that a product will fall. If this still does not occur, the customer will be asked to make another selection or will be refunded their money.