On October 15, 1985, this court certified to the Secretary of State a modified ballot title after petitioners, Portland General Electric (PGE) and William June, sought review under the provisions of ORS 250.085. After the decision was published, this court was notified that the Secretary of State and the chief petitioners had not been served as required by ORAP 15.05(3).1 The chief petitioners, Lloyd Marbet, Gregory Kafoury and Arthur Honeyman, moved to intervene. They asked this court to dismiss PGE’s petition and vacate our decision. We heard arguments on the matter on November 6,1985.
We have considered both the prejudice to the chief petitioners and the sufficiency of the Attorney General’s original ballot title, which the chief petitioners had already printed and circulated while unaware of the ballot title challenge and subsequent change. Because we reach the merits of the ballot title after reargument, we need not address the consequences of the failure to serve the Secretary of State and the chief petitioners.2
ORS 250.085(4) as amended by Oregon Laws 1985, chapter 447, section 6, requires us to review contested ballot titles for “substantial compliance” with the statutory requirements that they be concise, impartial and written so as to avoid confusion, ORS 250.035, 250.039. We have reexamined the Attorney General’s ballot title in light of the arguments presented to us by the chief petitioners and now conclude that the ballot title as originally drafted by the Attorney General meets this standard.
Our former opinion is vacated and the original ballot *337title certified to the Secretary of State by the Attorney General is reinstated.3
ORAP 15.05(3) provides:
“* * * The petition shall show proof of service on the following persons, if those persons participated in proposing, revising, or in any manner affecting a state measure:
“(a) The “chief petitioner” or “chief petitioners” referred to in ORS 250.045.”
Although the chief petitioners filed affidavits intended to establish some prejudice, until now we have had no rule of law concerning the establishment of prejudice. In future cases where persons are not served as required by ORAP 15.05(3) the burden will be on the party failing to show proof of service that those who were not served were not prejudiced by that failure.
The original ballot title reads:
PROHIBITS NUCLEAR POWER PLANT OPERATION UNTIL PERMANENT WASTE SITE LICENSED
Question: Shall all Oregon nuclear power plant operations be prohibited until the federal government licenses a permanent radioactive waste disposal site?
Explanation: (1) This measure prohibits all Oregon nuclear power plant operation until the Oregon Energy Facility Siting Council finds that a federally licensed high level radioactive waste disposal site is available to immediately accept plant waste for permanent disposal. Waste retrieval option for reprocessing is not required.
(2) If legislature declares an emergency need for electricity not available from other resources, including conservation, temporary suspension or repeal of part (1) of this measure must be referred to voters.