Can Sunscreen Cause Cancer?

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For decades, "slip, slop, slap" campaigns have stressed the importance of wearing sunscreen to help prevent skin cancer. And as millions of Australian families head to the beach this summer, sunscreens will be dutifully packed in every beach bag.

But there are early warning signs that rather than offering sun protection, some nanoparticles used in sunscreens could actually accelerate sun damage to skin.

Last year, the director of CSIRO’s Nanosafety research program told The 7.30 Report that: "the worst case scenario, I suspect, could be development of cancer. But we don’t know. That’s what we’re trying to find out".

Funnily enough, it was researchers working for BlueScope Steel, manufacturer of pre-painted steel roofs, who identified a range of particularly high risk nano-sunscreen ingredients. In 2006, BlueScope Steel was regularly being asked to replace roofs which displayed signs of premature ageing. To its surprise, the company found clear fingerprints and hand marks in sections where the roofs showed greatest damage.

The roof damage was traced back directly to workers installing the roofs wearing nano-sunscreens — and leaving behind a tiny residue of nanoparticles where they had touched the roofs. Sections of pre-painted steel roof that had been exposed to the nano-sunscreens showed degradation that was up to 100 times faster than unexposed areas.

In a peer-reviewed scientific study published last year, researchers from the company demonstrated that five out of six tested nano-ingredients in commercial Australian sunscreens behaved as extreme photocatalysts, aggressively generating free radicals when exposed to UV light and water.

The effect of nano-sunscreens on human skin remains unclear, and will obviously differ from their effect on pre-painted steel roofs. Nonetheless, the identification of extreme photocatalysts in products designed to provide sun protection has provoked concern in the international nanotoxicology community.

The familiar substances used in sunscreens behave differently when in tiny nanoparticle form. In larger particle form, zinc oxide and titanium dioxide, for example, are usually white and opaque. When ground down to nano-size, these particles become transparent, making it possible to use them in clear sunscreens.

In 2006 the national sunscreens regulator, the Therapeutic Goods Administration (TGA), estimated that 70 per cent of titanium dioxide-based sunscreens and 30 per cent of zinc oxide sunscreens contained these minerals in nanoparticle form.

So nanoparticles are used broadly in sunscreens and the early evidence suggests that many nanoparticles used in sunscreens behave as extreme photocatalysts. You might think that sunscreen safety would be of paramount importance in Australia, a country with one of the highest rates of skin cancer in the world — but the TGA is yet to ask manufacturers to conduct safety testing on nano-ingredients.

A large number of regulators — at least seven at the federal level alone — are charged with oversight of nanotechnology in Australia, which is a major impediment to the effective regulation of nanotechnology’s health and environment risks. And some regulators are more willing than others to acknowledge that existing regulatory systems are not capable of managing the new risks of nanoparticles.

Whereas the national cosmetics regulator NICNAS has begun consultation to introduce new regulations to manage nanotechnology risks in cosmetics and industrial chemicals, the TGA is refusing to close regulatory gaps regarding sunscreens.

The TGA has justified its failure to regulate the use of nanoparticles in sunscreens with the claim that there is no evidence that these nanoparticles penetrate the dead outer layers of intact adult skin. It says this means there is no risk to living cells.

However scientific studies have shown that skin penetration occurs in nanoparticles not used in sunscreens, especially when skin is flexed, damaged or exposed to "penetration enhancing" ingredients — such as those found in many sunscreens and cosmetics.

In a journal article published last year, researchers at the Australian National University and Monash University argued that uncertainty around skin penetration by nanoparticles in sunscreens warrants the TGA taking a precautionary approach to their regulation.

In recent correspondence with Friends of the Earth, the TGA said that it did not think the BlueScope Steel findings justified action to take photocatalytic nanoparticles out of sunscreens — or even to require companies to submit safety data that is relevant to the nano-form of the mineral they’re using.

We’re now enjoying a second summer since the BlueScope Steel findings were published and the sunscreens identified as extreme photocatalysts may still be in use by Australians anxious to protect their skin from sun damage.

Teenagers with acne, babies with thin skin, or people with skin conditions such as psoriasis or eczema may be using these sunscreens. Without mandatory labelling of nano-ingredients, there is no way for people with skin more vulnerable to nanoparticle penetration to choose a nano-free sunscreen.

The European Parliament has recently amended its cosmetics laws  to ensure that sunscreens and cosmetics which contain nanoparticles undergo mandatory safety testing and labelling to provide consumer choice. It is unacceptable that in Australia, where sunscreen use is necessarily widespread, and the risks of skin cancer acute, the TGA continues to resist calls for the effective regulation and labelling of nanoparticles used in our sunscreens.

The use of risky nanotechnology ingredients in high-exposure personal care products does not only present new threats to public health, it creates negative public perceptions of nano-product safety more broadly. Without decisive government action to regulate toxicity risks, and adequate nano-ingredient labelling to ensure consumer choice, a public backlash could damage other sectors of this burgeoning industry.

Over the summer break, millions of Australian families will be applying sunscreen daily. What better time for Innovation Minister Kim Carr to consider the benefits of pulling recalcitrant regulators into line and putting public health and consumer choice ahead of the interests of some reckless nanotechnology operators?

Friends of the Earth have recently published a new Safe Sunscreen Guide.

New Matilda

New Matilda is independent journalism at its finest. The site has been publishing intelligent coverage of Australian and international politics, media and culture since 2004.

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