General Motors is recalling 50,249 2011-2013 model-year Chevrolet Volts because they may pose a risk of carbon monoxide poisoning if the driver mistakenly thinks the engine is turned off when the car is actually idling silently on electric battery power, USA Today reported.

If the plug-in hybrid car is parked in a closed garage, for example, and idling in electric mode, eventually the gasoline engine will turn on to recharge the electric battery. As a result, people may become exposed to a carbon monoxide buildup.

Dealers will address this problem with a software update that restricts the period of time the car can be left idling in the “on” or “run” position.

These vehicles currently sound a chime to warn the driver if he or she exits the car when it’s still running. However, GM is aware of two people who say they suffered injuries because of the confusion, the newspaper reported.