Dunkin’ Donuts will change its powdered doughnut recipe so it no longer includes titanium dioxide, a whitening agent, a Dunkin’ Brands official said.

The change comes after an environmental advocacy organization said it found titanium dioxide nanoparticles in the white powdered sugar used, based on independent laboratory tests in 2013. The group As You Sow said the small size of nanomaterials makes them more likely to enter cells, tissues and organs and cause damage.

The FDA does not have a broad stance on products containing nanomaterials, saying it would make safety judgments on an individual basis.