Transportation Secretary Brock Adams said yesterday he will re-examine the use of airbags as safety devices in cars.

Adams said the re-examination is necessary because smaller, lighter cars must be built in the future to help the nation reduce gasoline and oil consumption and environmental pollution.

"Smaller, lighter cars are not going to be as safe unless you build in safety standards," Adams said. "I think we have to set these standards because a smaller, lighter car is the only way you're going to get both [good] emission standards and fuel standards at the same time," he said.

Adams' comments on the interview program "Meet the Press" (NBC, WRC) gave the first public inflation that he intends to go against the airbags decision made by his predecessor, William T. Coleman Jr.

Coleman ruled Dec. 6 against requiring airbags on all new cars. He said such a requirement would force on the public "an unfamiliar and controversial technology" that in the long run, could prejudice attitudes and prevent widespread acceptance of the lifesaving passive restraints.

Adams said yesterday that he could not "rationalize" Coleman's decision. "We're going to do airbags over," he said, referring to his planned re-examination.

Airbags are balloon-like devices designed to inflate automatically in thousandths of a second in frontal crashes, protecting front seat riders. Adams said their use must be reconsidered because Congress has eliminated mandatory seat belt use.

"I think we should re-examine airbags because they operate automatically," Adams said. "We were not successful in having the other passive restraints - mandatory seat belts with [ignition] interlocks - because Congress said you couldn't do it," he said.

However, he cautioned that airbags should be used in conjunction with seat belts on cars. Seat bealts are needed to protect passengers in roll-over accidents, he said.

Asked about the prospect of eliminating cars and making better use of energy resources by relying on mass transit, Adams said: "Mass transit will work only in [heavily populated] areas at this point . . . We will not force people out of their automobiles by regulation. The economic considerations of fuel and environment will do that."

In other energy-related matters yesterday, Interior Secretary Cecil D. Andrus said his department is investigating charges that some producers have withheld critically needed supplies of natural gas.

Andrus, appearing on the interview program "Face the Nation"; (CBS, WTOP), said the investigation was prompted by Sen. Howard Metzenbaum (D-Ohio), who requested the probe after charging that large amounts of natural gas are being withheld.

Andrus said he could not comment on the validity of Metzenbaum's charges, but he said he would have a report on the matter early this week. A larger investigation will be launched if there are grounds for doing so, he said.