that is what was told to me, that all filling manufacturers do not disclose the full ingredients. hal, i trust only because he is known as the father of the amalgam removal movement and i would not be alive if not for him and would have never known mercury was in fillings. he wrote the first book on it in the US and has studied it for 30 yrs or more.
update, 3M corp will disclose full ingredients if you are willing to sign a non-disclosure form. there may be others that do this for you, as well, but most do not. in the US, only hazardous ingredients are required to be disclosed.