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Europe may call TiO2 a carcinogen

Inhalation studies in rats spark push for classification

by Melody M. Bomgardner
June 19, 2017 | A version of this story appeared in Volume 95, Issue 25

Credit: Shutterstock
TiO2 puts the white in paint.
This image shows an open bucket of white paint with a used paint brush.
Credit: Shutterstock
TiO2 puts the white in paint.

The risk assessment committee of the European Chemicals Agency (ECHA) has proposed that the white pigment titanium dioxide be classified as a potential carcinogen. The move was requested by Anses, the French environmental and occupational health agency.

TiO2 is the world’s most widely used white pigment. It provides white color, opacity, and UV blocking to consumer goods including paints, plastics, paper, foods, cosmetics, and medicines. It is also used in tattoos and toothpaste.

In 2015, Anses asked ECHA to classify TiO2 as a presumed carcinogen by inhalation, citing studies in rats that resulted in the formation of malignant tumors. The request noted that the World Health Organization’s International Agency for Research on Cancer (IARC) has listed TiO2 as possibly carcinogenic to humans since 2006.

The ECHA committee concluded that TiO2 is a potential carcinogen, which is a less restrictive legal status than a presumed carcinogen. It says studies suggest the carcinogenic action of the pigment is due to inflammation and oxidative stress on the respiratory system. The ECHA committee agrees with Anses that toxicological effects are due to TiO2’s biopersistence and poor solubility.

The ECHA committee, like IARC, bases its classifications on data solely about hazard, not exposure. Still, the hazard characterization could result in requests for more research or labeling requirements. The European Commission must make a final decision.

The Titanium Dioxide Manufacturers Association, a trade group, says it is disappointed by the recommendation. TDMA argues that the rat studies are related to a mode of action that occurs only in rats.

“There is a vast body of scientific evidence that does not support a classification of TiO2 for humans, which is supported by over 50 years of epidemiological data on more than 24,000 workers and demonstrates there is no link between cancer in humans and exposure to titanium dioxide,” TDMA says.



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