The chairman of American Home Products Corp. testified in anage-bias case Wednesday that a clerical error was to blame forthe continuation of a policy requiring employees to seekpermission if they wanted to keep working after age 65.

Jack Stafford, the defense’s star witness in the suitbrought by a former assistant vice president, said the policyshould have been removed from the company’s standards manual whenthe Age Discrimination in Employment Act, 29 U.S.C. Sec. 621 etseq., took effect in 1979.