In Finishing

We may receive a commission when you use our affiliate links. However, this does not impact our recommendations.

Titanium dioxide powder.

It’s not just solvents such as methylene chloride that are coming under scrutiny as suspected human carcinogens. (I wrote about methylene chloride in the June, 2017 issue of Popular Woodworking.) The European Chemicals Agency’s Committee for Risk Assessment (RAC) just classified titanium dioxide as a suspected cause of cancer.

What is titanium dioxide (TiO2)? It’s a white inorganic pigment that occurs naturally in certain rocks and mineral sands. It has been used for decades in many products, including paints, cosmetics, sun blockers, foods, most toothpastes, and pills and tablets.

TiO2 is unique in several respects. It is whiter than other white pigments, often referred to as the “whitest white,” but more importantly, it has an extremely high refractive index. This refers to how much light is bent or refracted when entering a material. So titanium dioxide has better tinting strength and opacity than other pigments. It’s often used in non-white paints, in addition to white, to improve these two qualities.

Titanium dioxide also reflects harmful radiation, so it’s used in sun blockers.

The RAC bases its conclusion on the same type rat studies the EPA uses in its conclusion that methylene chloride, used in paint strippers, causes cancer. The coatings industry has pushed back the same way the stripper manufacturers have, saying there’s no evidence TiO2 causes cancer in humans.

If this finding by the RAC passes up through the chain of regulatory bodies in the usual way, we will soon find that many of the common products we use will include a warning that they include substances that are suspected carcinogens. Or the products will be reformulated, so as not to include this warning, and they won’t be as effective.

– Bob Flexner

Product Recommendations

Here are some supplies and tools we find essential in our everyday work around the shop. We may receive a commission from sales referred by our links; however, we have carefully selected these products for their usefulness and quality.

Recent Posts
Showing 4 comments
  • moonchaser

    And eventually everything will be outlawed…

  • IrritableBadger

    The biggest user of methylene chloride outside of the coatings industry is the beverage industry. They use it to decaffeinate naturally caffeinated agricultural products like tea leaves and coffee beans. A good eight hour soak strips the caffeine right out.

    Titanium dioxide is the whitest material on Earth, which is why it is so ubiquitous in consumer products as well as health products like sunscreen.

    My point, is that the intended end use isn’t addressed in carcinogen studies. If your corner coffee shop is out of decaf they’re not going to add a little methylene chloride to your latte. You’re also not going to be rubbing your kids down with titanium dioxide powder when they go to the beach.

    There’s absolutely no benefit to the consumer if they stick a known carcinogen warning label on paint or sunscreen. The sunscreen issue, in particular, presents a whole new challenge.

    While it’s semi-viable to use methylene chloride alternatives in a lot of processes, there is no alternative to titanium dioxide as a semipermeable protective coating for human skin. Nothing even close.

    Forty years of educating the public about the importance of sunscreen is billions of dollars gone for nothing if they put a carcinogen warning on the bottle.

    This rush to be perceived as safe is creating unknown threats in the next generation of products. Taxpayers are getting screwed on this deal.

  • Matt_Rob

    Titanium dioxide sounds like the Holy Grail of paint additives or so thought the Black Knight.

  • DaveS2

    Everything gives you cancer
    There’s no cure, there’s no answer
    Everything gives you cancer
    Don’t touch that dial
    Don’t try to smile
    Just take this pill
    It’s in your file
    Don’t work hard
    Don’t play hard
    Don’t plan for the graveyard
    Everything gives you cancer

Start typing and press Enter to search