WASHINGTON - Senators John Kerry (D-MA), Lindsey Graham (R-SC) and Joe Lieberman (ID-CT) are struggling with how their climate and energy bill will affect oil companies under a carbon control plan, though they have refuted claims that they will end up increasing gas taxes, Congress Daily reports.

The senators have floated the concept of a "linked fee" on oil and gas companies, which would tie to the carbon market price for other industries instead of grouping oil companies directly into a cap-and-trade program. ConocoPhillips, BP and ExxonMobil Corp. have expressed support for the idea.

However, the idea is under "serious revision," according to Congress Daily. "We're still working on it," Graham said. "I don't know where we're going to come out."

Kerry denied earlier this week that the bill would raise the 18.4-cent per gallon gas tax, saying, "There is not even a linked fee. There's no tax; there's nothing similar."

Graham, too, was adamant that the trio would not support such a tax. "At the end of the day I'm not going to support a gas tax. I think I know what one is and I'm not going to support it," Graham said. "And you don't need to support it. A gas tax doesn't change behavior."

Kerry and Lieberman said that they are on track to unveil a plan Monday, while Graham expressed reserved optimism. "That's the hope. I don't know. We'll see what happens here. . . There's a lot of moving parts on this thing."