Causes titanium dioxide cancer

Can titanium dioxide cause cancer?

Reliable scientific evidence shows that titanium dioxide is safe and does not cause cancer. Here is everything you need to know.

Titanium dioxide is a bright white pigment that is used in many different industries because of its unique and useful properties. It is predominantly used in everyday products such as paint, plastic, paper, and inks.


Current scientific evidence shows that products containing titanium dioxide are safe:

  • Decades of in-house and independent research have found no evidence of a potential cancer risk for humans from titanium dioxide.
  • Studies linking titanium dioxide to an increased risk of cancer are based on the effects of high concentrations in the lungs ("overload"), as observed in rats exposed to very high doses of titanium dioxide by inhalation. Such high doses are higher than those to which workers are exposed on a daily basis, and the effect observed in the lungs is not replicated in humans.



Titanium dioxide is a proven and ubiquitous natural substance. It is used in many everyday products such as paint, plastic, food, and cosmetics. Titanium dioxide - also under its chemical name TiO2 or known as food coloring E171 - has been reviewed by a large number of regulators and has been rated as safe for many different uses.

Lately there has been speculation as to whether it could be harmful to humans or even cause cancer. Here are the facts.


Differentiation between inhalation and ingestion

There are two distinct discussions about the safety of titanium dioxide: first, some concerns have been expressed about the potentially harmful effects of inhalation of dust; Second, the uptake of titanium dioxide in the form of the food coloring E171 was also discussed.

It is important to distinguish between these two areas. So, below, we set out what science has to say about each of the two.


1 / Titanium dioxide has been classified by the EU as a category 2 carcinogenic substance if inhaled. What does that mean?

In 2020, the EU classified titanium dioxide in powder form as a potential carcinogen if inhaled in accordance with the Classification and Labeling Regulation (CLP).

However, this classification is not based on new findings on possible dangers to humans from titanium dioxide, but on decades-old data on inhalation by rats and a well-known dust hazard. There is no scientific evidence that titanium dioxide causes cancer in humans.

The EU authorities emphasized in the classification that it could be potentially dangerous to dust, such as B. titanium dioxide powder, inhale in extremely high concentrations over a long period of time.

Then why did the EU classify titanium dioxide? And what does the classification mean for the consumer? Read everything you need to know here.


Why did the IARC evaluate titanium dioxide as potentially carcinogenic by inhalation?

In 2006, the International Agency for Research on Cancer (IARC) concluded that there was insufficient evidence that titanium dioxide caused cancer in humans.

However, the agency concluded that titanium dioxide "may be carcinogenic in humans through inhalation" (Category 2b). Although she found insufficient evidence for this, a risk of cancer in animals could be identified.

Other "possible carcinogens" identified by the IARC are bacon, pickled vegetables and aloe vera. Over the course of its advisory body history, the IARC has assessed more than 980 substances and activities, and classified hundreds of them as potential risks.

The evaluation of titanium dioxide by the IARC is based exclusively on three rat studies that were carried out more than 20 years ago under conditions that are no longer acceptable according to the current test guidelines of the EU.

In addition, it is generally accepted that rats are particularly sensitive to the effects of “lung overload” that is not observed in humans.

The results of the IARC have not triggered any further regulatory measures in Europe.


Why did the EU classify titanium dioxide as a possible inhalation carcinogen more than 10 years later?

Following a proposal from the French authorities in 2016, the Risk Assessment Committee (RAC) of the European Chemicals Agency (ECHA) concluded in June 2017 that TiO2 meets the criteria for classification as a suspected cancerous substance (Category 2) if inhaled.

The RAC's position is clear: there are no robust carcinogenicity studies in species other than rats, and the relevance of these data for humans is unclear. In addition, the RAC opinion does not take into account the data on more than 24,000 workers, which show that there is no association between the incidence of cancer in humans and exposure to titanium dioxide.

The RAC found that for TiO2 The suspected hazard described does not specifically refer to this substance, but is common to all dusts / powders known as "poorly soluble substances with low toxicity".

The suspected hazard is related to the shape of these particles, which, if inhaled in very high concentrations over a long period of time, can overload a rat's lungs. This is also referred to as “lung overload”. This could lead to the carcinogenic effect seen only in rats but not in other species or in humans.

The decision of the EU to classify titanium dioxide as a possible carcinogen when inhaled is therefore not based on new scientific knowledge, but rather reflects an additional precautionary approach for the known risk of inhaling too much dust.


Are there any risks to consumers?

The RAC underlined that it “does not take into account the likelihood of exposure to the substance and therefore does not address the risk of exposure”. In other words, the RAC's opinion does not address the question of whether the described hazard will ever occur in the real world.

Studies on the toxicology of substances should also take into account the principle of dosage. We all know the phrase: "The dose makes the poison". All chemicals, including water and oxygen, can be toxic to humans if they are consumed in high to very high doses.

Many animal experiments test the effects of a substance using high doses that do not occur in the real world. This is the case with titanium dioxide. If the extreme inhalation conditions specified in the classification are removed, titanium dioxide is not harmful. The specific effects on animals cannot be transferred to humans either, e.g. B. the "lung overload" observed in rats.

This was confirmed at a meeting between the European Commission, Member States and interested parties. It was concluded that there are “negligible” concerns for consumers as exposure to inhalable titanium dioxide particles must be extremely high for the substance to be in any way harmful. Such conditions were considered unrealistic by the authorities under normal and foreseeable circumstances.


What does the classification of titanium dioxide mean for the consumer?

The European Commission's classification clearly states that the suspected hazard is due to TiO2 - Powder is restricted if inhaled in very high concentrations over a very long period of time.

This means that the classification is of very limited relevance to consumers. In most products there is TiO2 only contained in the final product and there is almost no risk of inhaling it. Likewise is TiO2 in finished products such as paints and plastics either insoluble or in solid form and cannot be inhaled.

Nonetheless, the classification means that some products may need to carry labels or statements warning of dust, even when it is unrealistic that consumers will be exposed to this hazard at all, and certainly not to a harmful extent. For other products, such as cosmetics and toys, a reassessment may be required to determine the safety of TiO2to confirm again.



  1. The EU classification is not based on new information or hazards;
  2. The suspected danger will not occur under real conditions or under realistic circumstances;
  3. The safety of titanium dioxide for humans is supported by data collected over decades.


2 / Is it safe to eat titanium dioxide?

Yes. E171, the food grade of titanium dioxide, has undergone rigorous European tests and classifications that have proven that titanium dioxide does not persist or accumulate in the human body.
Numerous studies have repeatedly confirmed the safety of E171.


What researchers and authorities say about the safety of E171

In 2015, a group of researchers from the Food and Environment Research Agency in the UK, the Food Institute at Tübitak Marmara Research Center in Turkey, and the RIKILT Institute of Food Safety in the Netherlands conducted a study of the oral consumption of nanoparticles and larger titanium dioxide particles .

Their investigations showed that there was no “significant internal exposure of the consumer to the nanoparticles”.

In 2016, the European Food Safety Authority (EFSA) reviewed the latest information on E171 when evaluating food additives that were authorized before 2009. EFSA found that the data on E171 did not indicate any health concerns for consumers. The safety of E171 is not influenced by the particle size as it does not get into the human organism.


Why did France decide to suspend the use of E171?

The French decision is mainly based on a study by the National Agricultural Research Institute (INRA) from 2017. However, the results of this study cannot be extrapolated to humans and have not been confirmed by comparable studies.

In 2017, a study by the French National Agricultural Institute (INRA) was published which found a risk of cancer for rats when ingesting titanium dioxide. Similar to the inhalation studies, however, the protocol used in this research does not suggest that ingestion could cause cancer in humans.

In fact, the INRA itself makes it clear that its results do not allow any conclusions to be drawn about human health and that they do not comply with the OECD guidelines for testing chemicals. Other studies carried out in accordance with OECD guidelines have not found any adverse effects at doses significantly higher than those used in the INRA study.

EFSA itself was asked to review the results of the INRA study in 2018 and came to the conclusion that they did not justify a revision of the safety approval of E171. In 2019 Michigan State University and the University of Nebraska Medical Center investigated the concerns raised by the INRA study. They used higher doses than the INRA, but still did not observe any statistically significant changes in connection with the use of E171 in various immune parameters or cancer in the gastrointestinal tract.

Former EU Commissioner for Health and Food Safety, Vytenis Andriukaitis, repeated this on February 20, 2019 and underlined that the use of titanium dioxide as an additive was not safety-relevant. The Commissioner also reiterated EFSA's conclusion that oral absorption of TiO2 extremely low and independent of the particle size.



  1. The French suspension of E171 is not based on new information;
  2. The European Food Safety Authority has repeatedly confirmed the safety of E171.