The theta/ecology symbol published for the first time on 25 October 1969. The symbol is a combination of the letters e and o, from the words environment and organism.
In the 21 April 1970 issue of "Look" magazine, the theta/ecology symbol was put into a U.S. style flag. In this first version the symbol was colored chartreuse, according to the Flag Bulletin. The colors represent "pure air and green land" and environmental action.
This flag is made from durable nylon material. The flag has two brass grommets for easy display.