A group of about 15 senior Senate Democrats on Tuesday engaged in the first of what’s likely to be several private discussions about whether their ailing colleague, Sen. Robert Byrd (D-W.Va.), can continue handling his duties as the chairman of the Appropriations panel, sources said.

The Senate Democrats met during their weekly leadership meeting that includes the elected party leadership, as well as a broader group of regional whips and officers. Byrd’s diminishing health was not the reason for the session, sources said, but came up during the Senators’ discussion about the upcoming debate over a $100 billion-plus supplemental spending bill on Iraq.

Byrd, 90, has been in and out of the hospital in recent weeks, and he missed a series of votes before the spring recess. Concerns have been mounting for some time about his ability to handle his appropriations duties, but so far, Senate leaders have been unwilling to take action.

One high-level Democrat, speaking on the condition of anonymity, said Senators on Tuesday raised “serious concerns about his ability to handle his appropriations work, especially with the upcoming hearings on the supplemental.

“They are struggling to try to figure out how to deal with the situation.”

Senators made no decisions Tuesday over how to proceed, but they are expected to continue vetting the sensitive issue in the coming days, the Democrat said. Some Democrats have suggested that Byrd cede the gavel entirely or perhaps take on an emeritus role on the spending panel.

“Questions were raised by people in the room that need to be addressed,” the Democratic source said.

So far, Senate leaders, led by Majority Leader Harry Reid (Nev.), have been reluctant to remove Byrd. Yet many Democrats feel the pressure is growing to address the matter since the supplemental deals with a major election-year issue — one that could prove critical for the party in power.

The Democrat said there are new concerns among Senators that the “pressure is too much and that we need to have stronger leadership exerted from the Senate Appropriations Committee.”