The Office of Civilian Defense (OCD) was established by President Franklin D. Roosevelt in May 1941. It was responsible for planning community health programs and medical care of civilians in the event of a military attack on the United States. It was an independent agency and not associated with the United States Department of War. It coordinated with the Chemical Corps of the Department of the Army regarding protective measures against chemical weapons. United States Public Health Service officers were assigned as medical consultants with OCD local district offices.

The Office of Civil Defense (OCD) was an agency of the United States Department of Defense from 1961-64. It replaced the Office of Civil and Defense Mobilization. The organization was abolished on July 20, 1979, pursuant to Executive Order 12148. Its duties were given to the Federal Emergency Management Agency (FEMA).  (Article from Wikipedia)