The Interior Department inspector general has opened an investigation into whether federal money was inappropriately used to pay for a celebration of the 20th anniversary of the Alaska Volcano Observatory that recognized its chief patron, Sen. Ted Stevens (R-Alaska), according to information obtained by Roll Call.

Sources say the IG is looking into the funding behind the event at the Russell Senate Office Building. Organizers of the event were the University of Alaska at Fairbanks, which runs the observatory, university lobbyist Martha Stewart and the U.S. Geological Survey, which manages the observatory’s funding.

At issue is whether federal dollars were used in connection with a lobbying event. Federal law prohibits the use of federal funds for such an activity, either directly through the Geological Survey or indirectly through the observatory, which receives much of its funding from Stevens’ earmarks.

The Geological Survey listed Stewart, who lobbies for the university on several topics, as the point of contact for the event. The March 19 press release announcing the reception raised questions about the event and the use of funds, sources said.

During the event, Stevens was given a plaque by the Geological Survey for his support of the observatory.

Stewart declined to comment directly on the investigation, saying only that “in order to find out the status of their investigation, you’d have to contact the Inspector General’s Office.”

Stewart did say the event was nothing more than a “birthday party” for the observatory and designed to educate lawmakers and staff about the program, not to lobby them.

The April 2 event was an “education opportunity and event,” Stewart said, adding that the sponsors also used it as a chance to offer Stevens a “thank you” for his work.

The investigation highlights the often close relationship among lawmakers, lobbyists, federal agencies and recipients of earmarks.

The university began the observatory project in 1988 as a way to help aircraft flying near the state’s active volcanoes avoid problems associated with changing air temperatures and volcanic ash caused by eruptions.

The observatory has long been a pet project of Stevens and has received millions in earmarks over the last 20 years as a result of his support.

This is at least the second investigation by the Interior Department IG to raise questions about a federally funded program connected to the university and Stevens.

Last year, the IG, in cooperation with the FBI, IRS and other agencies, opened an investigation into the Alaska SeaLife Center. According to sources close to the investigation, the inquiry has focused on whether the center was used to funnel money to his former chief of staff, Trevor McCabe, who also was a business partner of Stevens’ son, Ben.