Question

At what point should you open all windows and hatches when fueling?

Answer 1

The time when you should you open all windows and hatches when fueling would be: after fueling
After fueling process, there will be a residual of oil substance that surrounds your car that could be really toxic if it inhaled for a prolonged period of time. Opening your window and hatches will eliminate this residual from your car while you drive.

Answer 2

During fueling of the cars, there are normally toxic residuals found in the gas. In most instances you'll find that some gases have lead which is very harmful to our health and they can be easily absorbed into the blood system. Therefore in order to avid the intoxication, it's usually advisable to open the windows and hatches after fueling to enhance air circulation which will eradicate the toxic residues from the car environment.