WASHINGTON - A Senate panel is nearing a vote on a proposal to put tobacco under Food and Drug Administration regulation despite objections that such a move would only entrench the market position of the nation's No. 1 tobacco company.

The bill, which was expected to be approved Wednesday by the Senate health committee and is identical to House legislation, would give the FDA the same authority over cigarettes and other tobacco products that the regulatory agency now has over drugs, food, medical devices and other consumer products.

Specifically, it would let the FDA regulate the levels of tar, nicotine and other harmful components of tobacco products. Cigarette smoke alone contains some 4,000 chemicals, more than 40 of which are known to cause cancer. It also would restrict advertising.

The bill has broad bipartisan support though some Republican lawmakers believe it will do nothing to stop people from smoking. President Bush, FDA commissioner Dr. Andrew von Eschenbach and Health and Human Services Secretary Mike Leavitt oppose the legislation.

Philip Morris USA, maker of Marlboro, the nation's top-selling cigarette brand, supports the bill. R.J. Reynolds Tobacco Co. and others oppose the legislation, saying it would help cement Philip Morris as the market leader.

Smoking now kills more than 400,000 people a year. It accounts for nearly one in five deaths in the United States.