A flash fire in the ductwork of the State Department injured four people Saturday, including three who were sent to a hospital, fire officials said. One person was in a "life-threatening condition" and the other two people were in serious but non-life threatening condition at Washington Hospital Center, authorities said. The fourth person fell from a ladder and hurt his knee, authorities said. The fire started shortly after 11 a.m., as construction crews were working on the premises, said Lon Walls, a spokesman for Washington’s fire department.