Titanium Dioxide

Titanium dioxide is used in a variety of personal care products, including sunscreens, pressed and loose powders. It is a very effective UV filter, and of low risk in creams. However, when titanium dioxide is inhalable, as it is in loose powders, it is considered a possible carcinogen by the International Agency for Research on Cancer. Nanoized titanium dioxide does not appear to confer any unique health hazards, so it is also a concern when inhaled, but not when it is applied in lotions or sunscreens.

FOUND IN: Sunscreen, pressed and loose powders

WHAT TO LOOK FOR ON THE LABEL: Titanium dioxide, TiO2

WHAT IS TITANIUM DIOXIDE?
Titanium dioxide is a fine white powder that occurs naturally. It was first intentionally produced for use as a white pigment in 1923.[2] MORE...

 It is naturally opaque and bright, which makes it useful for use in paper, ceramics, rubber, textiles, paints and cosmetics.[3] It is also UV-resistant, which makes it effective in pigments that are likely to be exposed to considerable light, as well as for sunscreens. It is used in a wide variety of personal care products, including color cosmetics such as eye shadow and blush, loose and pressed powders and in sunscreens.

Titanium dioxide can form several different shapes, which have different properties. Some shapes can be converted to nanomaterials. Micronized titanium dioxide (also called “nano”) was introduced in the early 1990s.[4] Nanotechnology and micronization both refer to the practice of creating very small particles sizes of a given material (usually smaller than 100 nanometers; a nanometer is 1/1 billionth of a meter). At these small sizes, and at low concentrations, titanium dioxide appears transparent, allowing for effective sunscreens that do not appear white.[5]

Nanomaterials may be used in sunscreens and powder-based products, but companies are not required to list ingredient size or structure. For powders, companies are only required to list the ingredients; for sunscreens, since titanium dioxide is an active ingredient, the concentration must also be listed.[6]

HEALTH CONCERNS: Titanium dioxide in inhalable forms is designated as a possible carcinogen by the International Agency for Research on Cancer (IARC). As a result, there is concern about TiO2 in loose powders, but not in creams such as sunscreens.  MORE...

Cancer (Inhalation Exposure Only)
The International Agency for Research on Cancer designates titanium dioxide as a carcinogen, largely due to studies in animals that have found increased lung cancers due to inhalation exposure.[7] Evidence to date does not demonstrate increased cancers when exposures occur through the skin or swallowed. Human studies, mostly occupational studies TiO2 inhalation, have demonstrated mixed findings.[8]

Nano Titanium Dioxide
The prevailing data indicate that nanoized TiO2 does not pose hazards that are unique from those of larger particle TiO2. One concern about nanomaterials is possible skin penetration. The literature investigating this suggests that because nanoized TiO2 forms clusters, it does not penetrate the skin,[9] particularly to the deeper (dermal) layers of skin.[10] In response to concerns that nano TiO2 might more readily penetrate damaged skin, researchers applied nano-based sunsreens to pigs ears that had been sunburnt. TiO2 did not reach the deeper levels of the skin in the sunburnt tissue.[11] Nevertheless, toxicological testing of nanomaterials needs to take into account the effects on particle size on the ways that dose is estimated because smaller particles will have greater surface area by volume.[12]

Inhalation of nano Titanium dioxide is of concern, given the cancer concerns for TiO2 of any size. One study assessed the likely inhalation exposure of TiO2 from cosmetic powders and found that most nano particles of TiO2 were inhaled either as clusters of nanoparticles (agglomerates) or attached to larger TiO2 particles.[13] This meant the particles were inhaled into the upper parts of the lungs but did not reach the alveoli (the part of the lungs where oxygen is exchanged). Many toxicological studies of nanoized Titanium Dioxide inhalation assume alveoli exposure, so studies should explore effects on the upper parts of the lungs.[14]

VULNERABLE POPULATIONS: Everyone

REGULATIONS: The US National Institute for Occupational Health and Safety has set exposure limits for workers due to concerns about lung cancer.[1]

HOW TO AVOID: Avoid loose powders and blushes that contain titanium dioxide. Use caution as well with pressed powders, since they can become airborne when used.

Caveat: Titanium dioxide makes a very effective sunscreen in creams and lotions, and is one of the safest options available. Avoid it only in aerosolized sunscreens.

References

[1] NIOSH. NIOSH Pocket Guide to Chemical Hazards (2010). Available online:http://www.cdc.gov/niosh/npg/npgd0617.html. September 12, 2014.
[2] IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. (2010). Carbon black, titanium dioxide, and talc. IARC monographs on the evaluation of carcinogenic risks to humans/World Health Organization, International Agency for Research on Cancer, 93, 1
[3] IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. (2010). Carbon black, titanium dioxide, and talc. IARC monographs on the evaluation of carcinogenic risks to humans/World Health Organization, International Agency for Research on Cancer, 93, 1
[4] Schilling, K., Bradford, B., Castelli, D., Dufour, E., Nash, J. F., Pape, W., … & Schellauf, F. (2010). Human safety review of “nano” titanium dioxide and zinc oxide. Photochemical & Photobiological Sciences, 9(4), 495-509.
[5] Schilling, K., Bradford, B., Castelli, D., Dufour, E., Nash, J. F., Pape, W., … & Schellauf, F. (2010). Human safety review of “nano” titanium dioxide and zinc oxide. Photochemical & Photobiological Sciences, 9(4), 495-509.
[6] Lewicka, 2011.
[7] IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. (2010). Carbon black, titanium dioxide, and talc. IARC monographs on the evaluation of carcinogenic risks to humans/World Health Organization, International Agency for Research on Cancer, 93, 1
[8] IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. (2010). Carbon black, titanium dioxide, and talc. IARC monographs on the evaluation of carcinogenic risks to humans/World Health Organization, International Agency for Research on Cancer, 93, 1
[9] Schilling, K., Bradford, B., Castelli, D., Dufour, E., Nash, J. F., Pape, W., … & Schellauf, F. (2010). Human safety review of “nano” titanium dioxide and zinc oxide. Photochemical & Photobiological Sciences, 9(4), 495-509.
[10] Sadrieh, 2010
[11] Miquel-JeanJean, C, 2012
[12] Schilling, K., Bradford, B., Castelli, D., Dufour, E., Nash, J. F., Pape, W., … & Schellauf, F. (2010). Human safety review of “nano” titanium dioxide and zinc oxide. Photochemical & Photobiological Sciences, 9(4), 495-509.
[13] Nazarencko, 2012
[14] Nazarencko, 2012