Legislation introduced in the Senate would impose an "excess profits" surtax on major oil companies that lawmakers charged had gained an unseemly windfall because of the war in the Persian Gulf.

The bill, sponsored by Sens. Howard Metzenbaum, D-Ohio, and Joseph Lieberman, D-Conn., would tax at a rate of 40 percent large oil company profits that exceed the average profit for the preceding five years.Sponsors said the tax, scheduled to take effect for the 1990 tax year, would leave oil companies with 60 percent of the profits above the five-year average.

Metzenbaum said Tuesday the surtax would apply only to about 30 major oil companies with 1 percent or more of oil production, reserves, refining capacity or product sales.

Metzenbaum said the bill was needed due to the "extremely troubling and offensive" profits racked up by oil companies in the last three months of 1990, ranging up to 300 percent higher than the same period in 1989.