The case of the patriotic German chemist Fritz Haber illustrates many of the thorny issues at stake in the relation between science and ethical conduct. During World War One, Haber actively contributed to the German chemical weapons program, and directed the first use of chlorine gas in warfare at Ypres in Belgium. In 1919, Haber was awarded the Nobel Prize for discovering how to fix atmospheric nitrogen to synthesize ammonia. During his acceptance speech, he stated: 'In no future war will the military be able to ignore poison gas. It is a higher form of killing'.

Since the early 20th century, numerous international efforts have been made to establish an international agreement of the unacceptability of chemical weapons. These eventually resulted in the 1993 Chemical Weapons Convention that bans the possession and use of chemical weapons.  
 
The adoption and promulgation of codes of conduct has been identified as one means of raising awareness of the prohibition on chemical weapons. It also encourages states and individuals to adhere to their obligations under the Chemical Weapons Convention.