On November 13, Silkwood attended a local union meeting then got into her car to drive to Oklahoma City to deliver the manila folder of evidence, the results of her seven week vigil, to New York Times reporter David Burnham. Ten minutes later her car went off the road and Silkwood died. The state patrol ruled it an accident, saying "it's pretty clear she fell asleep at the wheel. She never woke up." While blood tests showed a small amount of alcohol and methaqualone (a prescription sedative) in her system, it is doubtful the amount was sufficient to induce sleep in ten minutes. A subsequent investigation by a private detective concluded that she had likely been forced off the road by another car; a dent in the rear bumper showed metal and rubber fragments, as if another car had rammed her from behind. The manila folder was not recovered from the site of the crash, though other personal effects were. A subsequent Justice Department investigation also ruled it an accident. Congressional hearings, along with a lawsuit on behalf of Silkwood's children, however, have revealed an intriguing and bizarre story to discredit critics, involving the FBI, newspaper reporters, and the nuclear industry, a story largely left untold. It is possible Silkwood's phone had been tapped and that she had been under surveillance for awhile. Union official Jack Tice has said that Silkwood had been alarmed prior to her death: "She was starting to think someone was out to get her."

The truth of what happened the night of November 13, 1974, may never be known. What is clear is that the death of Silkwood has become a rallying point for anti-nuclear activists and put the nuclear industry on the defensive. The Atomic Energy Commission confirmed three violations at the Cimarron plant, which eventually shut down. And a major questioning of the nuclear industry has occurred as a result of the revelations that have come to light. In a suit filed by Bill Silkwood on behalf of his grandchildren, a jury in May, 1979, awarded the Silkwood estate over ten million dollars in punitive damages and cleared Silkwood of the allegation that she had stolen plutonium from the plant. It also found that Kerr-McGee had been negligent and that someone had planted plutonium in her apartment. Though an appeals court overturned the decision, the Supreme Court eventually agreed with the lower court, reinstating the victory for the Silkwood family and saying that punitive damages could be awarded in cases involving the nuclear industry, effectively allowing state and jury regulation.