A patient in Japan was hurt mid-surgery when she passed gas that caught fire causing serious injuries to her body, a university hospital in Tokyo said on Friday.

The woman, in her 30s, was undergoing an operation that involved applying a laser to her cervix, the lower part of the uterus at the Tokyo Medical University Hospital in Shinjuku Ward on April 15.

The laser is believed to have ignited the gas she passed, a report released by the hospital said. The blaze burned much of her body, including her waist and legs, Japanese newspaper The Asahi Shimbun reports. Her current condition is unknown.

An external committee looked into the incident and  found that no flammable materials were in the operation room and that the equipment was functioning normally during the surgery.

“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.

According to ABC, the report recommended fire-fighting training for operating room staff and taking steps to physically prevent methane from interacting with laser beams.

The gas released when one “passes gas” is a combination of carbon dioxide, hydrogen, nitrogen, oxygen and methane, reports the Washington Post. 

Whilst most of the components of flatulence are innocuous, hydrogen and methane render the gas flammable.