A proposed interstate natural gas pipeline that would be buried just four to six inches under the runway expansions planned for the Salt Lake International Airport is a cause for safety concerns, Salt Lake officials say.

Salt Lake City has joined neighboring cities of Bountiful, North Salt Lake and West Valley City in filing motions to intervene with the Federal Energy Regulatory Commission. City officials say the environmental impact studies weren't broad enough to cover pressing safety concerns in urban areas."We want a better urban statement in the environmental impact statement, and we want to review the proposed siting. This is not to say we are opposed to the proj-ect," said Assistant Salt Lake Attorney Steven Allred.

A public hearing is scheduled Wednesday in the State Office Building Auditorium. Another hearing will be in Las Vegas on Monday.

Applications have been filed with FERC to build the interstate natural gas pipeline, stretching from Wyoming oil fields to California. Three companies have proposed to build pipelines. Kern River Gas Transmission Co. has proposed a 837-mile line; Mojave Pipeline Co. and the Wyoming California Pipeline Co. proposed a 389-mile pipeline; and El Dorado Interstate Transmission proposed a 381-mile pipeline.

The pipeline is scheduled for completion by 1990 and could carry a price tag as high as $815 million, said Jim Huppi, environmental planner for Salt Lake City.

The Kern River plan seems to have the most political support, and it is the routing of that proposal that is raising concerns among Utah officials.

Besides the route's proximity to airport runways, Huppi said other potential safety conflicts include both old and new landfills and Utah Power & Light Co. power trunklines.

The current route cuts off aircraft access to the city's foreign trade zone and snakes diagonally through undeveloped parcels of industrially zoned land. City officials say if the pipeline follows that path, it could hamper future development plans.

"We're concerned about the safety issue at the airport, and at the landfill," he said. "In terms of other issues, we're concerned about the impact of construction on the road system here, with the additional truck traffic."

Huppi said city officials aren't trying to scuttle the project but are just asking for some answers.

"We don't have any issue with the pipeline going through the city. We're a little disappointed that they (Kern River) didn't touch bases with us as they should have and as they keep telling everybody they did. We just don't want it to go where they want it to go right now."

The tremendous reserves of natural gas in Wyoming make a north-south route a distinct possibility. Utah's congressional delegation has written to FERC to support the Kern River route, as has the governor's office, according to U.S. Forest Service officials.

Even if FERC does approve the Kern River proposal, it would still need the approval of state officials and federal agencies across whose land the pipeline would pass.

Garth Heaton, the U.S. Forest Service's energy coordinator for Utah, said Bountiful, North Salt Lake and West Valley City have sent delegations to Washington, D.C., seeking to intervene with the Federal Energy Regulatory Commission on the issue. They claim they didn't have enough opportunity to comment during environmental impact studies by FERC.

Some Utahns have complained the proposal didn't get enough public attention, and that possible severe im-pacts of at least one pipeline weren't studied sufficiently. Among concerns cited was the permanent scarring of foothills, with construction corridors opening many new areas to off-road vehicle abuses.

The Kern River project seemed to cause more worry than the others.

This round of comments is being bootstrapped onto the environmental studies of WyCal's project. Officials said concerns about any of the projects can be made at this time.

Last year, WyCal filed its application to transport gas to the Bakersfield, Calif., area. A supplemental environmental impact statement will be prepared about this project, and the commission will also accept statements about the other pipelines.

Comments can be mailed to FERC at 825 North Capitol St., Washington, D.C. 20426, and testimony will be accepted at the public hearing.

"At that time I would assume that Bountiful groups, including government, will raise several issues" involving environmental concerns, Heaton said.

"It is a big project. It does have potential serious adverse environmental impacts."

The Forest Service, which is cooperating with the commission in the issue, wants to make sure that the public knows it will have a new chance to express comments, he said.

Copies of the environmental statement are available at the Bureau of Land management state office, the Wasatch-Cache National Forest headquarters in Salt Lake City, the State Office of Planning and Budget, and various state agencies.

FERC officials said Mojave's pipeline was favored for the project as far as environmental impacts are concerned. But political pressure has been applied to support the Kern River plan, according to Heaton. He estimated the Kern River project has about a 50 percent chance of approval.