Triclosan is a halogenated phenol, or organochlorine, compound that is not highly regulated but is widely used. It is an antimicrobial with antifungal properties that is found across North America, Europe, and Asia in various products.
Triclosan is approved for use that leads to human consumption, and has been described as not likely to cause any adverse health effects in children or adults who use products as intended. Unfortunately, TCS is not only intentionally part of a variety of products but is also a compound that makes its way into wastewater and the water treatment system in significant quantities. This has raised concerns of negative ecological effects on certain fish and is believed to contribute to antibiotic resistance. Furthermore, this source can lead to exposure to TCS above the levels studied when establishing its safety. Additionally, TCS has been found in human plasma and breast milk and has been implicated as an endocrine disruptor.
All of these are concerns that were not part of the original evidence for safety and widespread use, which has pushed its re-review date by the FDA up by ten years.
Disinfectants, detergents, toothpaste, mouthwash, and deodorant
Journal of Applied Toxicology
Critical Reviews in Toxicology
US EPA