A person shall not operate a motor vehicle on a highway unless the filling spout for the fuel tank is properly closed by means of a cap or cover composed of a noncombustible material that meets or exceeds applicable federal safety standards. This section does not apply to an electrically powered motor vehicle.
A.R.S. § 28-965
Fuel tank caps
Official source: Arizona State Legislature. Reproduced from public-domain Arizona statutes; confirm against the official source for the current text. Not legal advice.