Virtually all surgical fires are preventable, yet every year about 240 patients are set on fire in operating rooms across the country. Fear of litigation or bad publicity leaves incidents underreported in many instances. Adoption of precautionary measures has been slow, often implemented only after a hospital experiences an accident. Advocates say it’s not clear how many hospitals have instituted available protocols, and no national safety authority tracks the frequency, which is thought to injure patients in one of every three incidents.