The tax levied by RCW
82.08.020 shall not apply to sales for use in states, territories, and possessions of the United States which are not contiguous to any other state, but only when, as a necessary incident to the contract of sale, the seller delivers the subject matter of the sale to the purchaser or his or her designated agent at the usual receiving terminal of the carrier selected to transport the goods, under such circumstances that it is reasonably certain that the goods will be transported directly to a destination in such noncontiguous states, territories, and possessions.