William French Smith, attorney general, whose department prosecutes tax-code violations, invested in an oil and gas tax shelter that would have brought him $66,000 in deductions -- four times his investment -- although the Internal Revenue Service considers such shelters abusive.

He later agreed to forgo the deductions. Shortly before taking office in 1981, Smith accepted a $50,000 severance payment from a California steel company of which he had been a director for six years. After the payment was disclosed, Smith returned it. He also repaid $11,000 for improper use of a government limousine by his wife.

J. Lynn Helms, head of the Federal Aviation Administration, resigned in 1984 following news reports that over eight years he and an associate "bled dry" some businesses they had acquired as funds were shifted from one to another. The businesses also were reported to have several million dollars in government-guaranteed debts.

Max Hugel, chief of clandestine operations at the Central Intelligence Agency, resigned in 1981 following allegations by two former associates that he had engaged in improper financial dealings. Hugel said the allegations were unproven and untrue.

Isidoro Rodriguez, head of minority affairs at the Agriculture Department, was reported to have collected unemployment benefits while working as a government consultant before receiving his federal appointment. He was fired in 1983 after writing a controversial memo on civil rights policy.

Robert E. Rader Jr., a pending nominee to the Occupational Safety and Health Review Commission, was ordered by a federal judge to pay a $3,000 penalty last year for misrepresenting facts and failing to comply with court orders in a race discrimination lawsuit.

Sherman E. Unger, general counsel of the Commerce Department, was nominated for a federal judgeship despite the American Bar Association's finding that he lacked personal integrity and had lied to the ABA. Unger, who was accused of unethical courtroom maneuvers, tax avoidance and fraud, died in 1983 before the nomination was acted upon.

Jayne H. Gallagher, director of public affairs at the Housing and Urban Development Department, failed to report more than $300,000 in debts on her financial disclosure form, incurred when she and two business partners defaulted on more than $1 million in federal and New York state loans. HUD Secretary Samuel R. Pierce Jr. declined to take action against Gallagher.