The development of mesothelioma is dose related to asbestos exposure. Patients report history of moderate asbestos exposure several years to over two decades prior to the development of the disease. Course of the disease is usually rapidly progressive with most patients surviving less than two years post diagnosis.

 Excerpt from "McQueen: The Untold Story of a Bad Boy in Hollywood":

"Mesothelioma attacks the lining between the lungs and the chest cage. The particular form Steve had, called a high-grade malignancy, is particularly virulent, spreading wildly from the lungs to the other organs. By the time the cancer is detectable, the patient usually has just months to live. "I don't know anyone with the disease who's been cured," said the chief of oncology of a Culver City, California, medical center at the time. Chemotherapy was not ordinarily effective, nor was surgery.

Mesothelioma is most frequently seen in shipyard workers, construction workers, and miners. Cigarette smoking is not associated with the disease; it attacks smokers and non-smokers with equal frequency. mesothelioma is a cancer whose cause has been known since the mid-1960s: asbestos.

Steve had been peculiarly surrounded by asbestos all his life. It was often present in his place of work during his itinerant years when be picked up odd jobs-at construction sites, for example. Asbestos was used in the insulation of every modern ship built before 1976; it is found on sound stages, in the brake linings of race cars, and in the protective helmets and suits worn by race car drivers.

John Sturges remembers Steve telling him about an incident that occurred while he was stationed in the Aleutian Islands during his stint in the Marine Corps.

...Steve had been sentenced to six weeks in the brig. He spent the time assigned to a work detail in the hold of a ship, cleaning the engine room. The pipes were covered with asbestos linings, which the men ripped out and replaced. The air was so thick with asbestos particles, Steve told John Sturges, that the men could hardly breathe..."

After being told his condition was inoperable, Steve McQueen checked in to a controversial Mexican clinic. He underwent a torturous three month regimen involving animal cell injections, laetrile, and over 100 vitamin pills a day. But his health only deteriorated.

On November 7, 1980, Steve McQueen died of a heart attack in Mexico after undergoing an operation to remove a tumor from his abdomen.

NOTE: The protective helmets and suits worn by race car drivers (even during McQueen's time) use NOMEX, not asbestos as stated in the above excerpt and other books.