Eight people were injured in a gas explosion Saturday at a hospital in Iwaki, Fukushima Prefecture, according to officials of the local fire and police departments.
The blast occurred when staff of Matsumura General Hospital and engineers tried to remove helium gas from a magnetic resonance imaging machine at about 8:30 a.m., the officials said.
The explosion left seven people seriously injured -- three hospital employees, three from a medical equipment company and one from a cleaning firm. One employee of the company that delivered the MRI sustained minor injuries, the officials said.
The local authorities believe liquid helium exploded after evaporating as the hospital employees and engineers were extracting the substance from the MRI machine. The device was to be replaced with a new machine.
When exposed to air, liquid helium evaporates and its volume swells dramatically. If evaporation occurs suddenly, it can lead to an explosion.
The hospital is located in the center of the city.