Is Alginate Safe?
Alginate has been in everyday use in dental offices throughout the world since the 1940's.
Hundreds of millions of dental impressions have been taken and we are unaware of any stories of allergic reaction. These impressions were made inside patient's mouths which shows its safety even when used against mucous membranes which are the most delicate of skin tissues. Alginate is routinely used to make molds of infant's hands and feet as young as one day old.
One of the concerns with alginate is breathing the dust. Of course, it is not advisable to breath any dust, but since the development of "dustless" (extremely low dust) alginate formulas, this concern has largely disappeared.
Alginate is not reusable, but it can be safely and legally included in your normal waste stream and put in your local landfill.
See the discussion of Crystalline Silica in Alginate HERE.