Oregon Revised Statutes Public Health and Safety § 465.525

(1) For a fraction of a gallon, the fee imposed under ORS 465.520 and 465.523 shall be proportionate to the fee imposed on a whole gallon.

(2) If the fee is paid pursuant to ORS 465.520 and 465.523 on dry cleaning solvent that is subsequently resold or exported from this state and not reimported for use in a dry cleaning facility, the reseller or exporter of the dry cleaning solvent is entitled to claim a refund or credit for the fee on the dry cleaning solvent that was paid by the reseller or exporter. The Department of Environmental Quality may require a fee payer claiming a refund to provide proof that the fee was paid with respect to the dry cleaning solvent and proof of its use or sale in a manner not subject to fee assessment.