A new study reveals that small particles of zinc oxide, which are commonly found in sunscreens, can be toxic to the colon if accidentally eaten, according to a study in ACS’ Chemical Research in Toxicology Journal.

Zinc oxide particles in sunscreen that are smaller than 100 nanometers are more toxic because they are more soluble. If ingested, the direct particle contact could cause death.

Even though zinc oxide can be found in some foods and cosmetics, scientists are concerned about the potential toxicity of these nanoparticles in sunscreen because of the high risk of children ingesting it.

Their experiments compared zinc oxide nanoparticles with larger-sized particles and their effects on colon cells. The toxicity of the nanoparticles was twice as high as the larger size. Only about 0.1 ounce of sunscreen, or 2 grams, was the amount that if eaten, would cause damage to the colon cells.

Further research is being conducted to determine the effects on animals and people.

Click here to read more on this story from the Chemical Research in Toxicology Journal.