The chief executives of the nation's three largest steel companies met privately with top officials of the Environmental Protection Agency last week to discuss ways EPA regulations might be made less costly for the industry.

"It's not a question of relaxing any of our goals," said one EPA official who attended the meeting, but "there may be ways of achieving those goals using more cost-effective techniques."

Although sources on both sides close to the meeting (there was an earlier one in February) emphasized that neither the EPA nor the executives talked about relaxing any standards, Carter administration economic officials are becoming interested in diminishing the impact of some environmental rules in the interest of fighting inflation and stimulating business investment.

Charles L. Schultze, chairman of the Council of Economic Advisers, had pushed for cost-cutting alternatives in a controversial Labor Department ruling limiting worker exposure to cotton dust. However, Labor Secretary Ray Marshall apparently convinced the President to retain the most expensive aspects of the proposal.

The executives who met with EPA Administrator Douglas Costle last week were Edgar Speer, chairman of U.S. Steel Corp.; Lewis Foy, chairman of Bethlehem Steel Corp.; and George Stinson, chairman of National Steel Corp.

The meetings apparently grew out of a major report on ways to aid the domestic steel industry prepared by a task force headed by Treasury Undersecretary Anthony M. Solomon. That task force also recommended the series of minimum prices for steel imports the administration put into effect last March to try to stem the tide of low-cost foreign steel being dumped into the American market.

Sources close to the meeting said that among the topics discussed were changing EPA regulations from setting emission limits for each part of the complex steel-making operation to setting an overall limit for an individual plant, then letting the companies choose the most efficient way of reaching the level.

They also discussed making it easier for facilities to get environmental permits - granting a plantwide permit rather than individual water, aid and other licenses.

The steel makers apparently are interested in having some EPA standards relaxed when old facilities are modernized. At present, when a facility such as a blast furnace is modernized it must meet the same standards as a brand new blast furnace.

Steel officials claim that such regulations are a disincentive to upgrading old facilities - which do not have to meet the same standards if they are not modernized. The government has been pushing steel companies to make their facilities more efficient and modern to enable them to compete with newer steel plants in Japan and elsewhere.

EPA sources said, however, that the laws are clear and that it is probably "impossible" to grant waivers to companies that upgrade.

The steel industry and EPA have been at war for years, with steel companies complaining that many EPA orders are too costly, and sometimes impossible, to meet. The industry has suits outstanding against EPA rules - especially on standards regulating the amount of particles that can be discharged into the air. The agency also has many enforcement proceedings pending against steel companies.

Besides the two high-level meetings between ostle and the chief executives, there have been many meetings between EPA staff members and environmental experts in the steel industry, sources said.

Although neither side would characterize the meetings as anything more than "informative," or "friendly" or "useful," other administration sources said that steel is merely the most important of a series of reevaluations by environmentalists and the economists.

These reexaminations may lead to no change in policy at all, one official said, but the growing concern about lagging capital investment and inflation will make the situation "very interesting, at the least."