Triclosan is a commonly found germ-killing ingredient in sponges, cutting boards, hand sanitizer, and many personal care products including toothpaste. A National Oceanic and Atmospheric Administration study has found that one-third of the bottlenose dolphins tested off South Carolina and almost one-quarter of those tested off Florida carried traces of triclosan in their blood. The concentrations found in the dolphins are known to disrupt the hormones and growth and development in animal tests. It disrupts the function of the thyroid in rats. Triclosan builds up in fatty tissues, so it passes up the food chain from animal to animal, including humans.