In this March 12, 2002 file photo, Homeland Security Director Tom Ridge unveils a color-coded terrorism warning system in Washington created after the September 11th attacks.
From NBC's Pete Williams
Homeland Security Secretary Janet Napolitano is expected to announce tomorrow that the color-coded threat advisory system, launched after the 9/11 attacks but now more or less discarded, will be formally scrapped this spring.
DHS has for the past several months moved away from the threat system. The threat level was not changed, for example, after the underwear bombing attempt on Christmas Day 2009, after the car bomb attempt last year in Times Square, or when package bombs were detected on cargo flights last fall.
Instead, DHS has more directly communicated intelligence directly to those considered most likely to need it and has made information public without resorting to changing the threat level.
The system was frequently used after its inception, with the threat level changed 16 times after it was introducted in 2002.
But no changes have been made to the threat level in any sector since August 2006.