The elevator at 65 Mt. Auburn St. that fell from the fifth floor to the basement last month passed inspection twice last year.

"The elevator was safe at the time of the inspection," William P. Leary, Cambridge elevator inspector, said yesterday. He added, "If the safety device hadn't worked, I would have taken the elevator out of service."

The Harvard Housing Office lowered rent in the building after telling all the tenants recently they will be without elevator service for at least six months.

Second floor tenants will get a five-per-cent rent reduction, and an additional percentage point will be deducted for tenants on each of the additional five floors, Vladimir E. Alexandrov, professor of Slavic Languages and Literatures and a tenant of the building, said yesterday. "The Harvard Housing Office was quick in responding to the suggestion that rents be adjusted," he added.

Harvard Real Estate, Inc. (HRE) had discontinued elevator service when it leased the building about a year ago, Warren F. Clancy, superintendent of utilities services in the department of Buildings and Grounds (B&G), said last week.

Leary granted the elevator a temporary operating certificate after extensive repairs "giving us his blessing to use it," Clancy added.

Leary said he reinspected the elevator after additional cosmetic work was done, and then issued a full certificate of use.

The empty elevator carriage fell from the fifth floor to the basement December 12 after a tenant on the sixth floor summoned it.

An engineering defect probably caused the accident, but the actual cause is hard to pinpoint, Leary said.

The elevator's safety device should have "instantaneously stopped the carriage" if it were falling too rapidly, he said.

Ken Daly, property manager of HRE, said yesterday HRE is looking much more carefully at its other elevators, although it owns no other elevators similar to the broken one. "We are much more aware of the problems of old elevators," he said, adding that some of them may be upgraded or repaired.

"The elevator never really worked properly, despite the fact that repairmen often came to fix it," Mary Hughes, a longtime tenant of the building, said at the time of the accident.

Daly said he is accepting quotations for a new elevator system. A new elevator will cost approximately $80,000 to $100,000, Sally Zeckhauser, president of HRE, said after the accident.