Gov. Jay Inslee signs SB 6440, April 3, 2014. Imposing motor vehicle fuel taxes on compressed natural and liquefied natural gas used for transportation purposes. Revised for 1st Substitute: Imposing transportation taxes and fees on compressed natural gas and liquefied natural gas used for transportation purposes. (REVISED FOR ENGROSSED: Concerning compressed natural gas and liquefied natural gas used for transportation purposes. )