John R. McKean, chairman of the U.S. Postal Service Board of Governors, recommended that the Postal Service sign a $300,000 contract with a San Francisco law firm this summer that is a client of McKean's accounting firm, according to postal union officials.

The law firm of Littler, Mendelson, Fastiff & Tichy was hired in June by Postmaster General William F. Bolger to advise postal management on contract talks with postal unions. Bolger said yesterday that McKean had recommended the firm to him and sat in on part of his first interview with its partners.

McKean, who is president of an accounting firm in San Francisco that bears his name, also is the certified public accountant for the law firm, attorney George Tichy confirmed yesterday.

Federal statutes prohibit government officials from using their office for personal gain or for the enrichment of persons with whom they have business or financial ties.

McKean's role was disclosed earlier this week by an investigator for East Bay Local 1111 of the National Association of Letter Carriers, one of two unions in deadlocked contract talks with the Postal Service.

On June 15, the day Bolger signed a six-month contract with the law firm, McKean wrote to the postal board's executive secretary and disclosed that his accounting firm had a business relationship with the law firm. McKean said in the letter that he had removed himself from any discussions about hiring the firm to "avoid even any appearance of conflict of interest."

McKean could not be reached yesterday for comment, but the San Francisco Chronicle quoted him as saying that he didn't believe his actions had violated conflict-of-interest laws because Bolger had hired the firm, not him.

An official in the Office of Government Ethics said yesterday that the office is reviewing the matter.

Members of the board of governors serve part-time and are paid $10,000 a year plus $300 a day for each board meeting they attend.

McKean has sparked controversy in the past. In March, the Senate Judiciary Committee questioned McKean about loans he had arranged for White House counselor Edwin Meese III and White House deputy chief of staff Michael K. Deaver. McKean was under consideration for the postal board appointment when he arranged the loans that totaled $118,000. McKean told the committee, which was holding hearings on Meese's nomination as attorney general, that there was no connection between the loans and his appointment.

In July, McKean acknowledged that he and Bolger had hired a former postal board chairman as a $20,000-a-year consultant.

Bolger said yesterday that McKean had told him "straight out" when he first recommended the Littler, Mendelson firm that it was one of his clients. Bolger said he considered two other law firms for the Postal Service job but didn't interview them because they had worked for the Postal Service in the past and he was familiar with their work.