Signs on gas pumps across the nation caution "Do not use cell phone while pumping gas" or "Turn off cellular phone," but is there a real danger to talking or texting on your phone while pumping gas?

SAN ANTONIO — Most of us use cell phones, and most of us drive cars requiring us to fill up their tanks on a regular basis. In tonight's edition of VERIFY, we combine the two to examine a trendy rumor ...

You probably know this one! Smoking poses the biggest fire risk while pumping gas. One loose ember can ignite gasoline vapors in the air, setting anything nearby, including you and your car, on fire.