The very roads that would bring tourists into the Craters of the Moon area could doom its chances as a national park, Sen. Jim McClure says.

A National Park Service report on the site states the greatest threat to the future of the volcanic region is increased traffic through it, McClure told a Rupert town meeting on Wednesday.Local business groups proposing the park want a road constructed from the Minidoka-Cassia area across the desert to Arco. Estimates are the road could cost up to $30 million to build.

But existing roads might actually have to be closed to protect the area from the scores of motorists, McClure warned.

The Idaho Republican also said farmers and ranchers should be aware that parkboundaries likely would extend beyond the lava flows, taking away rangeland fromgrazing.

The only reason to build the park would be to protect the unique features of the Great Rift Zone, which the Park Service has recognized as a one-of-a-kind volcanic landmark, Democratic Rep. Richard Stallings told the group.

The proposed park also would take in the Big Southern and Cedar buttes, Crystal Ice Cave and other sites.

Some Park Service personnel retain a "no new parks" mentality held over from the Reagan administration. Park Service Director William Mott Jr., however, assured Stallings he would support whatever decision Congress makes on the Craters of the Moon.