CEDA

CEDA (Civil Emergency Defense Agency) is a fictional governmental organization in the Left 4 Dead universe. Matierials with the CEDA logo advising survivors can be found in numerous safe rooms.

"Safety Checklists" with a "CEDA" logo have been spotted around the now-deserted Fairfield, instructing residents to barricade themselves in their basements and wait for help to arrive.

They also instruct citizens to seal their windows and all other openings with plastic sheeting and duct tape, implying an airborne infection. However, one one sign in the safe room at the end of The Subway has been written on by another survivor, saying "NOT AIRBORNE.".