With v3.3 the chemmacros bundle supports not only English and German but also French and Italian. Other languages could easily be added if users want it. If you need another language simply a) send me an email to the address specified in the documentation b) add a comment to this post or c) file an issue on the bitbucket site.
A very special thanks goes to Jonas Rivetti for the providing the Italian translation of the H and P statements! With v3.3a they are now available in English, German and Italian.