Over a decade ago the preservative Thimerosal, which contains mercury, was removed from many vaccine supplies in the United States and abroad. Robert F. Kennedy, Jr. and Dr. Mark Hyman, examine the research literature on Thimerosal and argue that it should be removed from the vaccines that still contain it. They’ve written the book Thimerosal: Let the Science Speak, which makes the case for the elimination the chemical from the world’s vaccine supplies and replacing it with already available safer alternatives.