Emergency workers struggling to pump contaminated water from Japan’s stricken nuclear complex fled one of the troubled reactors today after reporting a huge spike in radioactivity, with levels 10 million times higher than normal in the reactor’s cooling system.

Radioactivity in contaminated water in one reactor unit at a damaged Japanese nuclear power plant tested 10 million times higher than normal, forcing the evacuation of workers and again delaying efforts to bring the complex under control, the plant’s operator said today.