The fire occurred at the Tokyo Medical University Hospital in Shinjuku Ward on April 15. The patient in her 30s was undergoing an operation that involved applying a laser to her cervix, the lower part of the uterus.
The laser is believed to have ignited the gas she passed. The blaze burned much of her body, including her waist and legs.
In a report released by the hospital on Oct. 28, a committee of outside experts who looked into the case said no flammable materials were in the operation room at the time of the surgery.
The equipment for the operation was also functioning normally, it said.
“When the patient’s intestinal gas leaked into the space of the operation (room), it ignited with the irradiation of the laser, and the burning spread, eventually reaching the surgical drape and causing the fire,” the report said.