Mobil Corp. has agreed to pay $100,000 to the Environmental Protection Agency and to take other actions to settle charges that Mobil stations sold unleaded gasoline contaminated with lead.

The settlement, which does not imply an admission of guilt on Mobil's part, requires the firm to promise to tighten quality control when it transports gasoline from the refinery to gas stations.

It also requires the company to sponsor a campaign to warn motorists about putting leaded gasoline in cars designed for unleaded gasoline. A Mobil spokesman said the firm would distribute information to customers at Mobil stations and include the message in the company's regular advertising.

Leaded gasoline can ruin a car's catalytic converter and significantly increase pollution emissions from cars designed to run on unleaded gas. Under the Clean Air Act, companies are responsible for their gasoline, even if contamination occurs in tank trucks owned by a private distributor or at stations that are not company-owned.

An EPA spokesman said spot checks by the agency found about two dozen Mobil stations around the country selling unleaded gasoline with more than the permissible 0.05 gram of lead per gallon. He said such contamination, which shows up in about 1 percent of the EPA's spot checks of gasoline stations, is usually caused by the failure to clean a tank truck thoroughly before changing its load from leaded gas to unleaded, by seepage or by similar factors.

"It doesn't look like anything intentional," another EPA spokesman said. "If it had been an intentional thing, the action might have been more severe."