The Titainium Dioxide microparticles in the sunscreen are a real concern for this anon.
Titainium dioxide power is used as a whitener, and coating on chewing gum and is shown to cause Ulcerative Colitis, Crohn's, and Inflammatory Bowel Disease, making it illegal to use in the European Union.
The epithelium seems to find this powder to be toxic/carcinogenic, regardless of what "the papers" say.