Oregon Revised Statutes Revenue and Taxation § 319.090

(1) If any dealer sells, distributes or uses any motor vehicle fuel without first filing the certificate and bond and securing the license required by ORS 319.030, the license tax provided in ORS 319.020 shall immediately be due and payable on account of all motor vehicle fuel so sold, distributed or used.

(2) Except as otherwise provided in this subsection, the Department of Transportation shall proceed forthwith to determine, from the best available sources, the amount of such tax, and it shall immediately assess the tax and interest in the amount found due, together with a penalty of 100 percent of the tax, and shall make its certificate of such assessment and penalty. The department may waive all or part of a penalty imposed under this subsection if the department determines that a violation of the requirement under this section to file the certificate and bond or to secure the license was due to reasonable cause and without intent to avoid payment of the tax. In any suit or proceeding to collect such tax, interest or penalty, the certificate is prima facie evidence that the dealer therein named is indebted to the State of Oregon in the amount of the tax, interest and penalty therein stated.