American Red Cross President Mark Everson was forced to resign Friday after six months on the job because he had a "personal relationship" with a female subordinate, the nonprofit disaster-relief organization said.

The Red Cross's board "concluded that the situation reflected poor judgment on Mr. Everson's part and diminished his ability to lead the organization in the future," the Washington-based group said in a statement on its Web site.

Everson, 53, was Internal Revenue Service commissioner before accepting the Red Cross job in May. At the time, the organization was restructuring after congressional criticism of its response to Hurricane Katrina. The board asked for and received Everson's immediate resignation, the statement said.

"I am resigning my position for personal and family reasons, and deeply regret it is impossible for me to continue in a job so recently undertaken," Everson said in a statement on the Red Cross Web site. Calls to Everson at his home weren't immediately returned.

The board was made aware of the relationship by a senior Red Cross executive about 10 days ago, spokeswoman Suzy DeFrancis said in an interview. Everson acknowledged the relationship, and an executive committee of the board recommended his ouster, she said.

Everson addressed the full board Friday morning, and the 28-member panel voted unanimously to oust him, she said. The female subordinate, who wasn't identified, remains with the Red Cross.

The former executive is married to Nanette Everson, a former White House lawyer under President George W. Bush who later served as general counsel of the Commodity Futures Trading Commission until last March. They have two children.

Everson, who also was chief executive officer, was replaced by Mary Elcano, the organization's general counsel, on an interim basis. A search committee formed by the board will start to look for a permanent replacement, the statement said.

Everson's resignation is the latest turnover at the top of the embattled organization.

In December 2005, Marsha Evans resigned as president after the board expressed concerns about her management in the wake of Hurricane Katrina earlier that year. Bernadine Healy quit as chief executive officer in October 2001 amid criticism of plans to spend money from a fund set up for the families of victims of the Sept. 11 terrorist attacks, Red Cross spokeswoman Carrie Martin said in an interview today.

Last year, the Red Cross was fined by the U.S. Food and Drug Administration for violating a 2003 agreement to ensure the safety of the nation's blood supply.