Passengers board a Metro train are seen at the Chinatown station on Monday. (Pablo Martinez Monsivais/AP)

The ethics committee of Metro’s board of directors has concluded that Chairman Mortimer L. Downey did not violate conflict-of-interest rules by serving as a paid adviser to an engineering company that has lucrative contract ties to the transit agency.

In a Nov. 6 memo to Downey, the ethics committee, made up of four fellow board members, said it had reviewed Downey’s long-term business relationship with engineering giant Parsons Brinckerhoff and “determined that no additional investigation or action is warranted.”

“I am not surprised,” Downey said Monday, referring to the committee’s decision. “I don’t know why these things pop up. It doesn’t make my life any fun.”

Downey, a former deputy transportation secretary in the Clinton administration, was appointed to Metro’s governing board by the General Services Administration in 2010 as a representative of the federal government. He has made no secret of his approximately $100,000-a-year consulting deal with Parsons Brinckerhoff, which began five years before he joined the Metro board and ended last spring.

“I disclosed this every year” in annual financial disclosure forms that all Metro board members are required to file, Downey said. “And it was approved by the [transit agency’s] general counsel every year.”

After Metro came under growing public criticism this year for its severe financial problems and for the subway system’s chronic, sometimes calamitous breakdowns, Downey said, he ended his involvement with Parsons Brinckerhoff in May to avoid generating more controversy for the transit agency.

The company, which has been paid $81 million in recent years to manage Metro’s capital improvements program, had a major role in designing and building the troubled Silver Spring Transit Center. Parsons Brinckerhoff has been sued by Metro and Montgomery County over alleged problems with the three-story transit hub, which opened in September after five years of delays and $50 million in cost overruns.

The Washington Post first reported Sept. 28 that the D.C. Office of the Inspector General had filed a conflict-of-interest complaint against Downey stemming from his relationship with Parsons Brinckerhoff, even though Downey was no longer involved with the company. The complaint was referred to Metro’s ethics committee.

Washington City Paper first reported on its Web site Friday that the complaint against Downey had been dismissed, after the newspaper obtained documents from the D.C. inspector general under the city’s Freedom of Information Act.

One of the documents shows that the inspector general closed its case concerning Downey on Oct. 8. This apparently occurred after Metro’s ethics committee agreed to review the complaint.

The District government has declined to comment on the matter. The five pages of records given to City Paper include several redactions and shed little light on the specifics of the complaint. The paper said the inspector general’s office withheld more than 200 pages of documents related to the case.

Downey, who became board chairman early this year, said he was interviewed in October by Metro’s chief ethics officer, Phillip Staub, as part of Staub’s inquiry for the committee. He said that Staub, who did not reveal specifics of the complaint, asked him not only about his ties to Parsons Brinckerhoff, but also about his past consulting relationship with Kawasaki Rail Car, which is building 748 new subway cars for Metro.

“Prior to me being on the board, or even thinking about being on the board, Kawasaki’s counsel asked me to give them some advice,” Downey said Monday. “So I had two meetings with them, and that was it. It wasn’t about Metro. It was about the potential of high-speed rail in America. They were gathering information before making a business decision.”

Staub reported his findings to the committee.

“The [Metro] Board of Directors Ethics Committee investigated the ethics complaint filed against you,” the committee said in its Nov. 6 memo to Downey. “Based on the Ethics Officer’s preliminary investigation, the committee has determined that no additional investigation or action is warranted.”

As chairman of Metro’s governing board, Downey also is chairman of the ethics committee. But he recused himself in this case and was replaced on the committee by board member Anthony R. Giancola, also a federal appointee.

The other board members on the ethics committee are Fairfax County Supervisor Catherine M. Hudgins (D), D.C. Council member Jack Evans (D) and lawyer Michael Goldman, the acting committee chairman who signed the memo to Downey. Goldman represents Maryland on the board.

Goldman has declined to comment on the matter beyond acknowledging that the committee had received a complaint about Downey and the engineering company.

Downey has said that under his deal with Parsons Brinckerhoff, he gave the company “strategic advice” on transportation projects. He said he initially worked eight days a month, then cut back to four days a month, and was paid about $100,000 annually.

Cliff Eby, a top Parsons Brinckerhoff official, has told The Post that the company “diligently maintained” a “firewall” between Downey and Metro­-related work.

In the lawsuit against Parsons Brinckerhoff, Metro is seeking $25.8 million in damages, alleging poor design and management work by the company in building the Silver Spring facility, including deficiencies that Metro said will make the center more expensive to repair and maintain. Parsons Brinckerhoff has denied the allegations.

As for the ethics complaint, “I’ll be happy to have this taken off my permanent record now,” said Downey, who might be nearing the end of his tenure as board chairman, and even as a board member, at the beleaguered transit agency.

On Nov. 5, as members were meeting in a closed session to approve the hiring of a new general manager, a reporter tweeted that Downey was being pressured by others on the board to step down as chairman.

Speaking to reporters after the closed session, Downey said, “I have not been asked to step down from anything.” However, after his first term as chairman ends in early 2016, he said, “the nominating committee will make a decision . . . and I doubt I will want to be considered for another year as chairman.” He added, “I doubt I’ll be asked.”

Members had just announced that Metro’s new general manager will be former Maryland transit official Paul J. Wiedefeld. He will replace Richard Sarles, 71, who retired in January as the transit agency’s chief executive.

Discussing his status on the Metro board after the Nov. 5 closed session, Downey, 79, sounded tired of the stress involved in overseeing the agency.

“Totally unexpectedly,” he said, “I ran into Rich Sarles last Friday night when we were both in [a theater] balcony watching ‘Hamilton’ in New York. He looked good. I said, ‘Rich, what’s the secret?’ He said, ‘I’m having the best year of my life.’ ”