on 26 october 2011 yokosuka held its annual nuclear accident evacuation drill. this drill was first held in 2008 when the nuclear-powered aircraft carrier uss "george washington" was employed at the us naval base near this city. about 70 people, residents and firefighters took part in the drill. firefighters ordered the residents of the city to stay indoors, assuming abnormally high levels of radiation around the us base. radioactive contamination was controlled in the emergency response center by city officials. the us navy refused to take part in all this, because of the impossibility of radiation leaking outside the base. however, in december 2011 another drill was scheduled with yokosuka and other cities to prepare for the possibility that people on board the ship might be exposed to radiation.