:Is the Lt. Col a reliable source according to the wiki guidelines? Anyway, i´m no legal expert so I´m not going to try to build a case why phosphorus bombs are chemical weapons. The fact that the OPCW thinks that pb used against people makes them chemical weapons should be enough. It´s unlikely that the organisation charged with the implimentation of the CWC would say something that would contradict the treaty. I can give you a quote from  wthe wikipedia article http://en.wikipedia.org/wiki/Chemical_weapons   

 :Under this Convention, any toxic chemical, regardless of its origin, is considered as a chemical weapon unless it is used for purposes that are not prohibited (an important legal definition, known as the General Purpose Criterion). 

 :With my imperfect legal knowledge I think this the reason why the OPCW thinks that the use of pb against people makes it a chemical weapon (pb short for phosphorus bomb)