The state's new health insurance exchange, MNsure, won't be allowed to keep certain creative details of its marketing campaign private.

The Department of Administration on Thursday denied a July 8 request by MNsure officials to keep "unique, creative and proprietary marketing themes" out of the public eye.

Even though billboards went up this week featuring Minnesota's mythical lumberjack Paul Bunyan and fabled companion Babe the Blue Ox, the ruling could affect the rollout of a yearlong campaign, MNsure officials said. MNsure may consider an appeal or seek a change to state law.

"We identified a gap in the law that did not cover our creative marketing materials," MNsure spokesman John Reich said. "It's a real concern."

MNsure is a new competitive marketplace established by the federal health law, where individuals and small-business owners will comparison-shop for health coverage starting in October.

As a taxpayer-supported organization, MNsure falls under rules that say it must seek permission from the state to shield its records from public view, even temporarily, as in this case. Thursday's decision means that the marketing data will become public Sept. 9.

In the ruling, Department of Administration Commissioner Spencer Conk said MNsure did not establish a compelling need to temporarily reclassify the data as private and that similar creative details have not been considered nonpublic by other government entities.

MNsure failed to sway the commissioner in showing how making the marketing themes public would "render unworkable" its role in carrying out the federal health law or the state law establishing the exchange. Conk said exchange officials also didn't make a strong-enough case that keeping its advertising message secret would adversely affect the health, safety or welfare of the public, or MNsure's well-being or reputation.

The ruling was a victory for advocates of open records, including the Minnesota Coalition on Government Information, which submitted a letter arguing that reclassifying government data should only be done if it serves "a compelling public interest." MNsure's marketing theme data "does not rise to meet such a threshold," the group wrote.

"We think the commissioner made the right call," Matt Ehling, chairman of the group's legislative issues committee, said of Thursday's ruling.

Some legislators, including Republican Rep. Peggy Scott of Andover, had also urged the Department of Administration to reject the request.

In seeking the exemption, MNsure officials said they were concerned about widespread misinformation about the federal law, sometimes called Obamacare. They said taxpayers would be on the hook if MNsure had to spend more money to counter arguments if "unaffiliated groups" tried to fraudulently obtain private consumer data or to charge consumers for information available for free through MNsure.

"We're not saying it's a secret forever," said MNsure's Reich. "It's a matter of timing. Launching a marketing campaign is about sustaining interest and controlling the message around the launch. It's a ­disservice to taxpayers … to dribble it out in an unorganized way."

MNsure and Minneapolis advertising agency BBDO Proximity earlier this week announced the first wave of a $9 million marketing campaign that will include radio, television, newspapers, buses, billboards and social media. They also have set up a booth at the Minnesota State Fair.

Jackie Crosby • 612-673-7335