Washington — Rep. John Dingell, the legendary Michigan Democrat whose efforts to expose scientific misconduct and improper charges for overhead costs at universities two decades ago earned him both respect and resentment, has been unseated as chairman of the powerful Energy and Commerce Committee.

Rep. Henry Waxman, a Democrat of California and a senior member of the committee, ousted Mr. Dingell on a secret ballot by House Democrats, 137 to 122. As chairman of the House Oversight and Government Reform Committee, Mr. Waxman has accused the Bush administration of manipulating science for political purposes.

Most researchers won’t be sad to see Mr. Dingell go. In the 1980s and 1990s, he held a series of widely publicized hearings in which he accused big-name scientists of covering up research misconduct by themselves or their colleagues. In two of the most high-profile cases, the researchers — Thereza Imanishi-Kari of the Massachusetts Institute of Technology, and Bernard Fisher of University of Pittsburgh — were ultimately cleared of wrongdoing.

Mr. Dingell also led an investigation into the improper billing of overhead costs by Stanford University. Stanford eventually agreed to pay back $1.2-million, in addition to $2.2-million it had returned earlier, and the government issued much tougher billing rules for all colleges, limiting the overhead rates that they could charge for administrative costs.

Mr. Dingell lost his chairmanship in 1994, when the Republicans swept into power. When Democrats regained control of the House, in 2006, some scientists feared that Mr. Dingell would resume his inquiries into academic research. But Mr. Dingell has stayed relatively quiet on the topic in recent years. A year ago, the committee said it was investigating possible tobacco ties among academic researchers leading a large, federally financed study of smoking, but nothing has come of that inquiry so far. —Kelly Field