Oregon Constitution Art. V § 8a

In case of the removal from office of the Governor, or of his death, resignation, or disability to discharge the duties of his office as prescribed by law, the Secretary of State; or if there be none, or in case of his removal from office, death, resignation, or disability to discharge the duties of his office as prescribed by law, then the State Treasurer; or if there be none, or in case of his removal from office, death, resignation, or disability to discharge the duties of his office as prescribed by law, then the President of the Senate; or if there be none, or in case of his removal from office, death, resignation, or disability to discharge the duties of his office as prescribed by law, then the Speaker of the House of Representatives, shall become Governor until the disability be removed, or a Governor be elected at the next general biennial election. The Governor elected to fill the vacancy shall hold office for the unexpired term of the outgoing Governor. The Secretary of State or the State Treasurer shall appoint a person to fill his office until the election of a Governor, at which time the office so filled by appointment shall be filled by election; or, in the event of a disability of the Governor, to be Acting Secretary of State or Acting State Treasurer until the disability be removed. The person so appointed shall not be eligible to succeed to the office of Governor by automatic succession under this section during the term of his appointment.