When I worked for the poison control center, we would often get calls about children ingesting sunscreen products. Many of them contain active ingredients that are salicylate compounds (similar to aspirin) and if ingested in a sufficient amount, could cause toxicity. Fortunately most children did not eat enough to cause a problem.
However, a recent study suggests that ingredients in sunscreens, including oxybenzone, avobenzone, octocrylene, and ecamsule are absorbed through the skin in larger amounts than expected, even when used as intended. The concentration also increases over time, indicating drug accumulation. While this may sound like a cause for concern, the effects of the accumulated drug in the amounts measured is unknown. Further studies are needed to determine the clinical significance of these findings.
The FDA is also taking a closer look at sunscreen safety. New regulations may require updated testing and labeling. Two ingredients, zinc oxide and titanium dioxide, are considered to be the safest. Two other ingredients, PABA and trolamine salicylate, which are not marketed in the United States, are considered unsafe. There are several other sunscreens for which there is not enough information to determine safety. These include cinoxate, dioxybenzone, ensulizole, homosalate, meradimate, octinoxate, octisalate, octocrylene, padimate O, sulisobenzone, oxybenzone, and avobenzone. These ingredients will be coming under increased scrutiny by the FDA. This doesn’t mean they are not safe, only that more information is needed.
For a safe day in the sun, long sleeves, hats, sunglasses and shade are always a safe bet, and sunscreens that provide a physical barrier (zinc oxide, titanium dioxide) are the best choice for now.