Some public health experts are questioning why menthol, the most widely used cigarette flavoring and the most popular cigarette choice of black American smokers, is receiving special protection as Congress attempts to regulate tobacco for the first time. The legislation, which would give the Food and Drug Administration the power to oversee tobacco products, would try to reduce smoking's allure to young people by banning most flavored cigarettes, including clove and cinnamon. But those new strictures would exempt menthol - even though menthol masks the harsh taste of cigarettes for beginners and may make it harder for the addicted to kick the smoking habit. For years, the public health authorities have worried that menthol might be a factor in high cancer rates in blacks. Menthol itself is a pungent organic compound derived from mint oils or synthesized. It triggers the body's cold-sensation receptors, without actually lowering temperature, when it is applied to the skin, eaten or inhaled. The reason menthol is seen as politically off limits, despite those concerns, is that mentholated brands are so crucial to the American cigarette industry. They make up more than one-fourth of the $70 billion market and are becoming increasingly important to the industry leader, Philip Morris USA, without whose lobbying support the legislation might have no chance of passage. "I would have been in favor of banning menthol," said Senator Judd Gregg, Republican of New Hampshire, who supports the bill. "But as a practical matter that simply wasn't doable." Even the head of the National African American Tobacco Prevention Network, a nonprofit group that has been adamantly against menthol, acknowledges that the ingredient needed to be off the bargaining table - for now - because he does not want to imperil the bill's chances. "The bottom line is we want the legislation," said William Robinson, the group's executive director. "But we want to reserve the right to address this issue at some critical point because of the percentage of people of African descent who use mentholated products." Supporters of the tobacco legislation, including the Senate bill's sponsor, Edward Kennedy, Democrat of Massachusetts, say that the bill addresses the potential health risks of menthol by giving the Food and Drug Administration the authority to remove cigarette additives, including menthol, if they are proved harmful. Menthol is particularly controversial because the public health authorities have worried about its health effects on blacks. Nearly 75 percent of black smokers use menthol brands, compared with only about one in four white smokers. That is why one former public health official said the legislation's menthol exemption was a "cave-in to the industry." "I think we can say definitively that menthol induces smoking in the African-American community and subsequently serves as a direct link to African-American death and disease," said the former official, Robert Robinson, who retired two years ago as an associate director at the Centers for Disease Control and Prevention's office of smoking and health. The legislation could soon be up for vote in both chambers of Congress, where it has broad support. It is by no means a sure bet - though not because of the menthol issue. Despite the support of Kennedy and 56 other sponsors in the Senate, the legislation faces some determined opposition from tobacco-state lawmakers who resist industry regulation. The White House has said it opposes the legislation, arguing that Food and Drug Administration regulation could create the false impression that tobacco is safe. The legislation is largely the result of negotiations during sessions in 2003 and 2004 between lawmakers, anti-smoking advocates and Philip Morris, a unit of Altria Group and the only major American cigarette company that supports the effort to regulate the industry.