Agar-Agar: A stabilizer and thickener that is transparent, odorless, and tasteless and is obtained from seaweed (mostly from Pacific and Indian oceans and Sea of Japan). Discovered in 1658. Used in drinks, ice creams, frozen custards, sherbet, meringue, baked goods, jellies, frozen candied sweet potatoes, icings, and other treats. Nontoxic with the exception of a rare allergic reaction.
Acetone Peroxide: a maturing additive for bleaching flour and dough, has a sharp acrid odor similar to hydrogen peroxide. Approval for use in flour, and in bread and rolls. Being a strong oxidizing agent it can be damaging to skin and eyes. The internet is full of instructions on how to make bombs our of acetone peroxide.
Winter R. A Consumers Dictionary of Food Additives. New York, NY: Three Rivers Press; 2009