Worcester firefighter Lt. Jeffery Dubeau, front, enters a building with other firefighters, right, on the campus of Worcester Polytechnic Institute, in Worcester, Mass., during a test exercise for safety tracking devices, in Worcester, Mass., Tuesday, Aug. 2, 2011. As the ten year anniversary of the Sept. 11 attacks approaches, researchers, fire fighters, and government officials are working to perfect technology that tracks the location and vital signs of first responders. (AP Photo/Steven Senne)