Some products containing nanoparticles do not mention this on their labels, while other firms are falsely claiming to have enhanced their products by using nanotechnology, the Brussels conference heard last week (10 June).
Dr Andrew Maynard, chief science advisor to the 'Project on Emerging Nanotechnologies' at the Woodrow Wilson Center, has collated an inventory of products currently on the market which manufacturers claim contain nanotechnology.
He said around 800 products have been identified online, with the bulk of these found in the health and fitness sector, but that few of these pose a potential health risk.
However, he is concerned that controversy surrounding nanotechnology – some of which, he says, is not grounded in scientific fact – has led manufacturers to remove any mention of nanomaterials from their products.
"We have seen some companies drop the 'nano' claim while continuing to use nanotechnology. This suggests nanotechnology is going underground," he said.
Harald Throne, researcher at the National Institute for Consumer Research in Norway, echoed concerns that companies may be becoming less inclined to highlight nanomaterials.
He searched a website run by a major international cosmetics company, using keywords like 'nanotechnology' and 'nano', to estimate how many products contain nanotechnology. Throne's search turned up 29 products in 2007, but when he repeated the same exercise recently, there were zero hits.
This, he said, suggests that companies may now view 'nano' as a negative label rather than an added value.
Sue Davis, chief policy officer at UK consumer advocacy group Which?, said data was limited, and expressed concern that companies are reluctant to engage with consumers on the issue.
"We have to distinguish between marketing hype and real uses of nanotechnology," she said, adding that her organisation had found it difficult to extract reliable information from industry.
She said Which? conducted a survey of 67 cosmetic companies but received information from just eight. All eight respondents reported using nanotechnology in sunscreen.
"However, if you go online you can find products advertising carbon fullerenes in anti-ageing creams and nanosilver in toothpastes, despite the potential toxicity associated with these substances," she said.
Davis called for mandatory reporting to combat the lack of information in this area, as voluntary codes do not work.
However, Steffi Freidrichs, director of the Nanotechnology Industries Association, said the industry has been upfront about its use of promising new technologies and that companies go to great lengths to ensure products are safe.
She pointed to confusion about the definition of nanotechnology, with some NGOs defining 'nano' as materials smaller than 300 nanometres, while the industry uses the definition of less than 100 nanometres.
"Varying definitions leads to claims that the industry is not open with information. But nobody is lying and nobody is misleading the public or authorities. Let's agree on what we're talking about and work together to inform consumers," she said.