The office of Michigan Gov. Gretchen Whitmer (D) announced the death. Mr. Dingell had complications from prostate cancer.

Mr. Dingell announced in February 2014 that he would not seek a 30th full term in Congress, and he was succeeded by his wife, Debbie Dingell. That November, President Barack Obama awarded him the Presidential Medal of Freedom, the country's highest civilian honor.

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Mr. Dingell had served as the representative from Michigan’s 15th Congressional District since 1955, when he won a special election to replace his father, John D. Dingell Sr., a New Deal Democrat who died of tuberculosis while in office.

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Known as “Big John” and “The Truck” for his forceful nature and his hulking 6-foot-3-inch frame, the younger Dingell rose to become chairman in 1981 of the Energy and Commerce Committee, which handled nearly half of the bills in the House and covered a sprawling policy realm including transportation, consumer affairs and public health.

When asked to define the jurisdiction of his committee, Mr. Dingell liked to point at a photograph of the Earth taken from space.

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He was one of the American auto industry’s most stalwart, influential friends on Capitol Hill, and invariably resisted efforts to regulate car manufacturers. In addition to repeatedly blocking more stringent fuel-efficiency and emissions standards, he staved off efforts to require safety features such as seat belts and air bags.

Michigan Democrat John Dingell, the longest-serving member of Congress, dies at 92 share Share View Photos View Photos Next Image

Mr. Dingell’s unwavering allegiance to the auto industry drew criticism, especially after his 1981 marriage to Deborah Insley, a senior executive at General Motors and a member of that company's founding family. One environmental lobbyist, a longtime foe of Mr. Dingell’s, said the congressman was “literally married to General Motors,” a charge Mr. Dingell denied.

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“I was fighting for autoworkers long before I met Deborah,” he told The Washington Post in 2010. “The fact is that I am not married to the auto industry, but I am elected to represent the people of Michigan and in our part of the country. My people live and die by the success of the auto industry and manufacturing.”

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In 1979, he sponsored a bill to prohibit federal spending on passive restraints such as air bags and accused the Transportation Department of concealing evidence that air bags were at risk of exploding and burning passengers. Five years later, he continued to attack the air bag as a “defective instrument” that “does not work except in head-on collisions and only in a fraction of those.”

“Because of his influence among the Democrats in the House, it was impossible to get a consistent Democratic Party stand over the decades for stronger regulation of the industry,” consumer-safety advocate Ralph Nader said. “So the existing standards became obsolete, and that was fine with him.”

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As forceful as he was about defending Detroit, Mr. Dingell was equally known for his aggressive efforts to root out government and corporate fraud as the chairman of the Energy and Commerce subcommittee on oversight and investigations. He was “an investigative powerhouse,” according to the New York Times. “Everything from nuts and bolts to blood banks, bottled water and cardiac pacemakers are unquestionably safer now because of Mr. Dingell’s efforts.”

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His inquiries brought down more than one government official, including lobbyist and former Ronald Reagan adviser Michael K. Deaver, who was convicted of perjury in 1987 after lying under oath during Mr. Dingell’s investigation of illegal influence-peddling.

Deaver received a three-year suspended sentence and a $100,000 fine, a punishment Mr. Dingell considered too lenient. “An ordinary citizen who steals a Social Security check, goes for a joyride or is caught with a few grams of marijuana goes to jail, but someone of wealth and influence who lies to a grand jury and Congress has little to fear,” he said at the time. “The message is: The powerful can get away with things most people can’t.”

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Mr. Dingell’s work on the subcommittee in the 1980s and early ’90s also discovered overbilling by hospitals and corruption within the generic-drug industry.

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An inquiry during the Reagan years into the withholding of millions of federal dollars meant to clean up a toxic waste site resulted in the resignation of an Environmental Protection Agency administrator, and Stanford University President Donald Kennedy resigned after revelations before Mr. Dingell’s panel that the school used federal money to pay for “research expenses,” including an antique commode, a 72-foot yacht and floral arrangements.

Mr. Dingell’s years-long investigation of scientific fraud at the National Institutes of Health led to the rare retraction of a research paper by Nobel laureate David Baltimore but ultimately found no wrongdoing and drew criticism of Mr. Dingell as an overzealous witch-hunter.

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“We do not wear lace on our drawers as we conduct our investigations,” Mr. Dingell told the New York Times in 1991. “I’m not paid to be a nice guy. I’m paid to look after the public interest.”

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His continued allegiance to the auto industry, however, cost him his job as chairman of the Energy and Commerce Committee.

In late 2008, outspoken environmental advocate Henry A. Waxman (D-Calif.) challenged Mr. Dingell for the position, calling the Michigan congressman “a determined opponent on clean air, climate change and energy issues.”

Waxman won the narrow race with the help of votes from newly elected Democrats who had been swept into office on the coattails of Obama’s promise of radical change.

Just weeks after he lost his chairmanship, Mr. Dingell played a key role in securing a multibillion-dollar bailout package to aid GM and Chrysler, which were in danger of collapse as the nation descended into recession. He continued to lobby for further aid through the 2009 federal stimulus package and the Troubled Asset Relief Program, which was primarily aimed at saving the country's large banks but ended up funneling billions of dollars to the two automakers.

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“Do you know what would have happened to my constituents if those companies had gone under?” Mr. Dingell told The Post in 2010. “I went through the Depression as a boy. My mother had to put paper into her shoes and walk around in the snow. . . . We had people starving to death. Do you think I'm silly enough to let that happen again?”

Raised in Washington

John David Dingell Jr. was born on July 8, 1926, in Colorado Springs into a family of Polish descent. He moved to Detroit as a boy and then to Washington when his father was elected to the House in 1932. He was a congressional page throughout his teenage years, and graduated from Georgetown Preparatory School in 1944.

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After serving in the Army in World War II, he earned a bachelor’s degree in 1949 and a law degree in 1952 from Georgetown University. He spent summers during school working as a park ranger in the Rocky Mountains and at Mount Rainier in Washington state, indulging in a love of the outdoors and hunting.

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He clerked for a federal circuit court judge for a year after college and in 1954 landed a position in Michigan as the Wayne County prosecutor. He held that job only briefly before his father’s death.

When Mr. Dingell was sworn into office in 1955, he pledged to continue working on issues that were important to his father.

He introduced legislation that created a Civil Rights Division in the Justice Department and became an indefatigable proponent of health-care reform, annually sponsoring the national health-care legislation that his father introduced in 1943. He presided over the House when Medicare was passed in 1965, and lent the gavel he had used that day to then-Speaker Nancy Pelosi (D-Calif.), who used it when the House passed the 2010 health-care overhaul.

Mr. Dingell's first marriage, to Helen Henebry, ended in divorce. Their daughter, Jeanne Dingell, died in 2015. In addition to his wife Debbie, survivors include three children from his first marriage, John D. Dingell III, Christopher Dingell and Jennifer Dingell; a brother; a sister; and three grandchildren.

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In retirement, Mr. Dingell became a social-media star as he took to Twitter with self-deprecating jokes and of-the-moment commentary. “Staff has now informed me of what a Kardashian is,” he tweeted in 2014, referring to the family famous for its tabloid appearances and reality TV shows. “I’m only left with more questions.”

Mr. Dingell was widely regarded as one of the more inscrutable members of Congress. He was a hunter and a onetime board member of the National Rifle Association, as well as a fan of Kennedy Center ballet performances. He was a former park ranger who co-wrote the Endangered Species Act and the Marine Mammal Protection Act, but became one of conservationists’ prime enemies for his fierce opposition to tightening fuel-efficiency standards.

“The ambiguity of our system is in a way summed up in Dingell, who handles it with great aplomb,” Rep. Timothy E. Wirth (D-Colo.) said in a 1983 interview with The Post. “He is now the best legislator in the House. The reason for that is his remarkable capacity to live with ambiguity, which you have to do up here. . . . The world isn’t simple, there are so many competing interests, each with a bit of the truth. If you try to stake everything out in terms of black and white, it will kill you.”