What is Titanium Dioxide (TiO2)?
March 25, 2024
Titanium (Ti) is a naturally occurring metal found in plants and animals. It interacts with oxygen to form titanium oxide found in soils, sand, and ores. It is commonly used for industrial and consumer products like paints, coatings, adhesives, cosmetics, paper, plastics, floor coverings, roofing materials, toothpaste, soap, pharmaceuticals, food colorants, and sunscreen.
Main Forms of Titanium Dioxide Production
Titanium dioxide is produced in 2 main forms:
- pigment grade titanium dioxide, 98% of the total production, and
- an ultrafine (nanomaterial) product.
1. Pigment Grade Titanium Dioxide
The pigment grade of titanium dioxide is a fine white powder that offers a bright white pigment and excellent light-scattering properties that provides opacity and whiteness to products like paints, coatings, plastics, and paper. It is used as a food coloring agent (E171) in products such as candies, toothpaste, and chewing gum. It is used as a photocatalyst in environmental applications like air and water purification, as it can accelerate certain chemical reactions when exposed to light.
2. Ultrafine (Nanomaterial) Titanium Dioxide
Ultrafine (nanomaterial) titanium dioxide has transparency properties and offers maximum ultraviolet light absorption. It is used as a UV-filtering agent in sunscreens to help protect the skin from the harmful effects of ultraviolet (UV) radiation by reflecting and scattering UV rays.
Regulatory Approaches to Titanium Dioxide Safety
The US Food and Drug Administration (FDA) has issued guidance that titanium dioxide pigment is safe for use as an additive in food as well as an ingredient in cosmetics and sunscreen. Health Canada in 2012, supported the safety of titanium dioxide in food. However, recently European authorities have taken a different stance. In May 2021, the European Food Safety Authority (EFSA) banned titanium dioxide as a food additive, due to inconclusive evidence that that titanium dioxide causes DNA or chromosomal damage in humans.
Titanium Dioxide Exposure
Workers tend to experience higher levels of exposure to substances, as a result the US Department of Labor’s Occupational Safety and Health Administration (OSHA) has established Permissible Exposure Limits (PEL) for titanium dioxide manufacturing and downstream manufacturing where workers may be exposed to titanium dioxide dust.
Consumers tend to be exposed to lower levels of titanium dioxide dust as it is only one ingredient of the product they are using.
Assessing the Toxicological Impact of TiO2 Nanoparticles
With the increased development of nanotechnologies and greater human and environmental exposure, TiO2 nanoparticles have come under toxicological scrutiny. Toxicological studies have shown that TiO2 nanoparticles cause adverse effects via oxidative stress resulting in cell damage, genotoxicity, inflammation, and immune response. The adverse effects vary depending on the physical and chemical characteristics of the TiO2 nanoparticles and the route of exposure. Based on animal inhalation studies, the International Agency for Research on Cancer (IARC) has classified TiO2 nanoparticles as “possible carcinogens to humans”. Nanoparticles can be inhaled into the lungs due to their extremely small physical size, and some studies have raised questions about their possible effects on respiratory health. The National Institute for Occupational Safety and Health (NIOSH) has classified TiO2 nanoparticles as an occupational carcinogen. Studies on dermal exposure to TiO2 nanoparticles, which humans absorb using sunscreens, indicate negligible skin penetration.
Areas for further research include long term exposure to sunscreen products, use as an additive for food and pharmaceutical products and human consumption, and long-term environmental effects on aquatic organisms. Until more toxicological and human exposure data is available, experts recommend caution with TiO2 nanoparticles and that it should be used with great care. Check with regulatory bodies and health care authorities for the most up to date information.
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