Legislation
Use of phenoxy (hormone-like) herbicides are restricted in Western Australia under the Aerial Spraying Control Act 1966 and the Agriculture and Related Resources Protection (Spraying Restrictions) Regulations 1979.
The herbicides covered are: Dicamba, MCPA, MCPB, Picloram, 2,4-D, 2,4-DB and 2,4,5-T.
Triclopyr (for example, Garlon™600 also contained in Grazon™DS) is a phenoxy herbicide but is not restricted by legislation. Nevertheless you should take similar precautions when using it.