U.S. Homeland Security Secretary Janet Napolitano says she is reviewing recommendations on the color-coded threat alert system and experts are evenly split over its usefulness.

She said the committee of experts that made the recommendations to her were "equally divided, 50-50" on whether the color-coded threat alert system developed after the Sept. 11 attacks was useful. It currently stands at "yellow" for elevated.

One recommendation the experts gave her is when the code becomes elevated, after a certain number of days it ought to automatically revert back to the lower level unless a decision is made to intentionally leave it higher.

"The problem is once you raise the level it is virtually impossible to reduce it for a number of political and public affairs reasons. So there would be an automatic revert once it were raised after a certain number of days," she said at a Reuters Washington Summit. "I think that kind of recommendation makes a lot of sense."

Any decision could impact airlines, and Napolitano said the Department of Transportation and other agencies would have their say after she makes her recommendation.