Four of the five senators investigated in the Keating Five scandal escaped formal punishment, but sharp rebukes delivered by the Senate Ethics Committee could haunt their re-election campaigns.

Ending the 14-month investigation, the committee decided "no further action is warranted" against Sens. Dennis DeConcini, D-Ariz., John McCain, R-Ariz., Donald Riegle, D- Mich., and John Glenn, D-Ohio.But the committee found all four used poor judgment and that the conduct of Riegle and DeConcini gave the "appearance" of being improper.

Despite the sharp words of dissaproval, the four senators were spared the humiliating ordeal of a trial by the Senate that seems to face the fifth senator, Alan Cranston, D-Calif., who was found guilty of an "impermissible pattern of conduct."

The five senators were accused of pressuring the Home Loan Bank Board on behalf of savings and loan wheeler-dealer Charles Keating who contributed $1.3 million to their campaigns and causes.

Cranston, who is 76 and suffering from prostate cancer, has already announced he will not run in 1992.

The committee has given Cranston the option of presenting additional evidence or petitioning for a new hearing, but it appears the only way Cranston can escape a Senate trial is to resign.

Although the committee did not find the case as strong against the other four senators, the judgment on each would be ideal ammunition for opponents to use against them should they choose to run again.

"We did not think there was anything we found in those four cases, under any reading of the rules, reached a level requiring institutional action," Sen. Warren Rudman, R-N.H., the committee's vice chairman, said.

He said that in the cases of Riegle and DeConcini, the committee's statement "contains very strong language. The words speak for themselves."

The panel said the conduct of Riegle and DeConcini "gave the appearance of being improper and was certainly attended with insensitivity and poor judgment."