Oregon Revised Statutes Revenue and Taxation § 307.420

(1) Before any exemption from taxation is allowed under ORS 307.405, the person claiming the exemption shall file with the county assessor a written claim for such exemption prepared on a form prescribed by the Department of Revenue and furnished by the assessor, and shall file with the assessor with the first claim for exemption the certificate issued by the Environmental Quality Commission under ORS 468.170 covering the property for which exemption is sought. The claim shall be filed not later than April 1 of the assessment year for which the exemption is claimed; except that if the person receives a certificate after April 1 but before July 1, the person may file a claim on or before July 15 of that year. The county clerk shall record the certificate in the county record of deeds, upon presentation by the assessor. Each year thereafter to continue such exemption, the taxpayer must file not later than April 1 a statement with the county assessor, on a form prescribed by the Department of Revenue and furnished by the assessor, stating that the ownership of all property included in the certificate and its use remain unchanged.

(2) If a claim required by subsection (1) of this section relates to state-appraised industrial property as defined in ORS 306.126 and is filed with the Department of Revenue within the time required by subsection (1) of this section, the claim shall be deemed timely filed with the assessor.