It’s always important to be safety conscious when refilling your vehicle at the gas pump, but it’s especially important in the winter. The reason for this is that static electricity is much more common in the winter. Static electricity is the result of a buildup of an electric charge in your body. In your car, you build up a charge as different layers of clothing rub together, and as your clothing rubs against your seat. In the winter, this charge continues to build up because the dry air doesn’t allow the charge to dissipate into water molecules in the air as it does in the summer. In addition, the soles of your shoes (if they are rubber) are insulators, and don’t allow the electricity to discharge.

So when you exit your car to refuel in the winter, you most likely have an electrostatic charge built up. If you don’t discharge this before you start fueling, it may discharge on the nozzle of the gas pump, ignite gas vapors, and start a fire. For this reason, it’s important to discharge any static buildup in your body before you begin to fuel. You can do this by touching your car door after you exit the car. The metal in the door will conduct the electric charge and remove the buildup in your body.

Here are some other tips for safe refueling:

• Turn off the car and stay near the nozzle when refueling.
• Don’t get back in the car while refueling, as this can cause you to build up a charge again. If you do have to get back in the car, discharge yourself on the door immediately when you get out.
• Refill approved containers on the ground, not in the vehicle. Keep the nozzle in contact with the container while filling it.
• If a fire starts, don’t remove the nozzle. Leave the area and get assistance.

Sources
http://www.wboc.com/story/24246452/tips-to-safely-refuel-at-the-gas-pummp
http://www.physics.org/article-questions.asp?id=44