WASHINGTON (AP) -- Government health officials said they can’t show how $5 billion spent on preparations for a bio-terror attack or flu pandemic has made the country safer.

Congress approved the money five years ago in response to the attacks of Sept. 11, 2001 and an anthrax scare triggered by tainted letters sent to congressional offices.

State health departments now typically get tens of millions of dollars to prepare for bio-terrorism each year, compared with hundreds of thousands before the attacks.

Congress set criteria and charged the Centers for Disease Control and Prevention with evaluating how well the dollars have been spent. CDC officials said improvement in emergency preparedness is hard to measure.

State health officials said the right questions are not being asked in the evaluations, but are at a loss to suggest anything better. One Tennessee official said “everything is so slippery and vague,” and many questions could be answered five different ways.