• What are the main health hazards associated with breathing in titanium dioxide?
• What happens when titanium dioxide comes into contact with my skin?
• Can titanium dioxide hurt my eyes?
• What happens if titanium dioxide is accidentally swallowed (enters the digestive system)?
• What are the long-term health effects of exposure to titanium dioxide?
• Will titanium dioxide cause cancer?
• Will titanium dioxide cause any problems with my reproductive system?
• Will titanium dioxide cause effects on the fetus/unborn baby?
• Will titanium dioxide act in a synergistic manner with other materials (will its effects be more than the sum of the effects from the exposure to each chemical alone)?
• Is there potential for titanium dioxide to build-up or accumulate in my body?

What are the main health hazards associated with breathing in titanium dioxide?

High concentrations of titanium dioxide dust may cause coughing and mild, temporary irritation.

Long-term inhalation of high concentrations of pigmentary (powdered) or ultrafine titanium dioxide may cause lung cancer, based on animal evidence. See "Will titanium dioxide cause cancer?" below for more information.

What happens when titanium dioxide comes into contact with my skin?

Titanium dioxide is a very mild irritant or non-irritant based on human and animal information. Application of 0.1 mg titanium dioxide powder in a non-occlusive chamber, once daily for 3 days to intact or damaged skin, produced almost no irritation (scored 0-0.4/4) in 5 volunteers.

Studies using sunscreen applications on volunteers showed that titanium dioxide particles only penetrate the outermost layers of skin.

Can titanium dioxide hurt my eyes?

Titanium dioxide is a very mild irritant or non-irritant based on animal information. There may be slight irritancy as a "foreign object", based on its physical and chemical properties. Some tearing, blinking and mild temporary pain may occur as particles are rinsed from the eye by tears. No human information was located.

What happens if titanium dioxide is accidentally swallowed (enters the digestive system)?

Titanium dioxide is not considered toxic if ingested. One historical case of human ingestion of one pound of titanium dioxide was located. No harmful effects were observed. Ingestion is not a typical route of occupational exposure.

What are the long-term health effects of exposure to titanium dioxide?

No conclusions can be drawn from the few studies that show respiratory effects in titanium-dioxide exposed workers, because of concurrent exposure to other substances that are well known to cause lung disease. There was no association between titanium dioxide exposure and increased mortality from any cause in a retrospective cohort mortality study of 4241 titanium dioxide workers.

LUNGS/RESPIRATORY SYSTEM:

A few human population studies or clinical studies involving titanium-dioxide exposed workers have shown effects such as decreased lung function, mild fibrosis, and thickening of the lining of the chest cavity (pleural thickening). However, the workers in these studies were also exposed to other substances including asbestos and/or silica, which are well known to cause lung disease. Therefore, no conclusions can be drawn.

In general, long-term exposures to high concentrations of dust may cause increased mucous flow in the nose and respiratory system. This condition usually disappears after exposure stops. Controversy exists as to the role occupational exposure to dust has in the development of chronic bronchitis (inflammation of the air passages into the lungs). Other factors such as smoking and general air pollution are also important, but dust exposure may contribute to this effect.

In animal studies, long-term inhalation exposure has caused persistent adverse effects on the lungs (e.g. inflammation, fibrosis, changes to alveolar cells), which are believed to result from dust overloading of the lungs. Effects with ultrafine titanium dioxide occur at much lower exposure concentrations than are required with the larger sized pigment grade particles. The effects are more closely related to lung burden in terms of the surface area rather than the mass of the particles.

SKIN SENSITIZATION:

Titanium dioxide is not a skin sensitizer. Negative results were obtained for 1% titanium dioxide in patch tests conducted on 38 orthodontist patients. A negative result was obtained in an unconfirmed animal test.

Will titanium dioxide cause cancer?

The International Agency for Research on Cancer (IARC) has determined that titanium dioxide is possibly carcinogenic to humans (Group 2B) based on inadequate evidence in humans and sufficient evidence in experimental animals. This conclusion relates to long-term inhalation exposure to high concentrations of pigmentary (powdered) or ultrafine titanium dioxide.

The available human studies do not suggest an association between occupational exposure to titanium dioxide and risk for cancer. Four studies from North America and western Europe are available in the literature. The largest study showed a slightly increased risk of lung cancer in titanium dioxide production workers in 6 European countries compared to the general population. However, there was no evidence of an exposure-response relationship. No increase in the death rates for kidney cancer was found when the occupational exposure group was compared to the general population. The other studies, conducted in Canada and the US, did not report an increased risk of lung and/or kidney cancer. All of the studies had design limitations.

Animal evidence shows that high concentrations of pigment-grade (powdered) and ultrafine titanium dioxide dust can cause respiratory tract cancer in rats exposed by inhalation and intratracheal instillation. Ultrafine titanium dioxide has increased lung tumour incidence at much lower exposure concentrations than is required with the larger sized pigment grade particles. The effects are more closely related to lung burden in terms of the surface area rather than the mass of the particles.

The series of biological events or steps that produce the rat lung cancers (e.g. particle deposition, impaired lung clearance, cell injury, fibrosis, mutations and ultimately cancer) have also been seen in people working in dusty environments. Therefore, the observations of cancer in animals were considered by IARC as relevant to people doing jobs with exposures to titanium dioxide dust.

Note: The primary particle size of pigment grade titanium dioxide is between 0.2-0.3 micrometres in diameter, although larger aggregates can be formed. The primary particle size of ultrafine titanium dioxide is 10-50 nm.

Will titanium dioxide cause any problems with my reproductive system?

No animal or human information was located. Titanium dioxide is probably not a reproductive hazard.

Will titanium dioxide cause effects on the fetus/unborn baby?

No animal or human information was located. Titanium dioxide is probably not teratogenic or embryotoxic.

Will titanium dioxide act in a synergistic manner with other materials (will its effects be more than the sum of the effects from the exposure to each chemical alone)?

No information was located.

Is there potential for titanium dioxide to build-up or accumulate in my body?

In animal studies, long-term inhalation of titanium dioxide results in impaired lung clearance with resulting accumulation of particles in the lungs. In a study using female rats, ingestion of 12.5 mg/kg/day titanium dioxide particles (particle size 500 nm) for 10 days resulted in deposition of particles in the liver and spleen and in lymph tissues associated with the digestive system. No particles were found in the heart or kidney. The persistence of the particles was not assessed.

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Document last updated on March 9, 2007

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