P Boffeta et al. Scandinavian Journal of Work, Environment and Health. August (2001) Vol.27 #4 p 227.
A case control study of a proposed association between exposure to titanium dioxide dust and lung cancer.
This was a small study, the main result was: for those classified with high exposure for 5 years OR = 1.0 (95% CI = 0.3 to 2.7).
Although not a powerful study, the result provides some confidence that any association between Titanium dioxide exposure and lung cancer is very weak.