The trip was the first of two Ridge made in late 2002 and early 2003 to spend time off at the Scottsdale, Ariz., home of prominent Bush-Cheney fund-raiser David Girard-diCarlo.
After the first visit, two of Ridge's aides were hired as homeland security lobbyists by Girard-diCarlo, whose political fund-raising in Pennsylvania in the 1990s was instrumental in Ridge's election as the state's governor.
At Girard-diCarlo's firm, Blank Rome, Ridge's former aides specialized in lobbying his newly created department.
"This relationship does raise questions about the integrity of the government's process for awarding contracts," said Robert Tuttle, a law professor at George Washington University. "It creates the appearance that Mr. Girard-diCarlo and his clients might receive preferential treatment."
On his first day in office, Mr. Bush issued ethics standards requiring his appointees to "endeavor to avoid any actions creating the appearance that they are violating applicable law or the ethical standards in applicable regulations."
Homeland security officials told The Associated Press they believe Ridge acted ethically because he paid his own way on the trips and never discussed business with Girard-diCarlo.
"David has never even mentioned any single client by name that's involved in homeland security with the secretary," Ridge spokesman Brian Roehrkasse said.
Blank Rome has lobbied Ridge's department on behalf of 29 companies, three nonprofit groups and a trade association for the software industry, according to reports the firm filed with Congress.
In a statement, the lobbying firm called Ridge and Girard-diCarlo "close personal friends for more than a decade.
"Their wives are close friends, and they often spend time together as families. They talk and get together on a regular basis, as good friends do," the firm said.
Ridge left his job as Pennsylvania governor to serve President Bush in coordinating a homeland security strategy after the Sept. 11, 2001, attacks.
The day after Mr. Bush signed legislation creating the department and announced that Ridge would run it, Ridge flew with his wife to Arizona, where he stayed for two or three days in Girard-diCarlo's gated-community home. Six days before Ridge's visit, Girard-diCarlo had taken out a $3 million loan on the newly built home.
The month after the trip, Mark Holman became the first of two Ridge White House aides to leave the government and go to work for Girard-diCarlo's firm on homeland security issues.
Ridge's chief of staff during his years as Pennsylvania governor, Holman had worked briefly for Girard-diCarlo's firm before Ridge brought him to the White House.
A federal conflict-of-interest law barred Holman from lobbying the White House for a year after his departure. The restriction, however, didn't extend to Ridge's new agency.
The other former Ridge aide, Ashley Davis, also lobbied the Homeland Security Department.
At the time of Ridge's trips to Arizona, Girard-diCarlo's firm represented Raytheon, one of a team of companies that Homeland Security recently awarded border protection work worth up to $10 billion over the next decade.
Girard-diCarlo's firm arranged two meetings in 2002 between Ridge's staff and Raytheon executives, who outlined the firm's capabilities in border security and other areas, according to Raytheon. Ridge was present for part of the first of the two meetings; Holman, in his role as an aide to Ridge, participated in the second meeting, the company said. The next year, as a Blank Rome employee, Holman lobbied Ridge's department on behalf of Raytheon, according to reports the lobbying firm filed with Congress.
Since early 2003, Blank Rome has lobbied Ridge's department on behalf of the technology services company BearingPoint. The department awarded a $229 million contract to the company in September.
The contracts for Raytheon and BearingPoint were competitively bid.