The government wants to declare land belonging to an oil refinery, an Army rifle range and Los Angeles International Airport as "critical" to the suvival of six endangered species of California butterflies.

The boundary lines are being drawn so the fragile butterflies can live in areas - sometimes of just a few acres - that will not affect operations of the airport, refinery or ordnance range.

The oil company already as put up a fence around a two-acre plot to keep people out of the tiny area where the last of the El Segundo blue butterflies live.

"We do have proof that some endangered species can coexist side by side with human activities," said Keith Schreiner of the Fish and Wildlife Service. "These fragile little pieces of habitat, some of which are only two acres . . . can support the butterflies because the insects need very little habitat to survive."

He said each of the six species of butterflies measures only about an inch in wingspan, and they rarely travel more than an acre away from plants they feed on in caterpillar stage.

Under endangered species laws, the government can declare areas as "critical habitat" for plants and animals in danger of becoming extinct, and federal agencies may not take any actions which would damage these areas.

The proposal defining habitat for the butterflies in 100 square miles along the California coast is to be published in the Federal Register next Tuesday and "excludes existing man-made structures or settlements," a spokesman said.

The butterlies include:

Lange's metalmark, which lives on several acres of sand dunes near Antioch. The same area is the only known home of the Antioch dunes evening primrose and Contra Costa wallflower.

El Segundo blue, which lives on two acres within the Standard Oil refinery in El Segundo and a larger area at one end of Los Angeles International Airport.