CARBON nanotubes are as light as plastic and stronger than steel, unique properties which quickly earned them a reputation as the wonder materials of the nanotechnology revolution.
Discovered 20 years ago and made from atom-thick sheets of graphite rolled into miniscule tubes, they are being developed for products ranging from energy-efficient batteries to stronger sports equipment and bullet proof vests.
But they are now also at the centre of safety fears about nano-sized materials. Research published last year suggests some nanotubes could be as deadly as asbestos if inhaled in sufficient quantities.
A British team found that long, thin, multi-walled carbon nanotubes had the same effects as asbestos fibres when injected into the abdominal cavity of mice. This is the established method of seeing whether materials have the potential to cause mesothelioma – a cancer of the lung lining that can take 30 to 40 years to appear following exposure.
Short and curly nanotubes did not behave like asbestos, researchers led by Professor Kenneth Donaldson of the University of Edinburgh reported in the journal Nature Nanotechnology. And questions remain, such as whether long nanotubes can become airborne, reach the lungs and work their way out to the sensitive outer lining, said the professor. “But if they do get there in sufficient quantity, there is a chance that some people will develop cancer.”
The study has galvanised calls for more research on the safety of nanotechnology and better regulation of this new science.
Assistant secretary of the Australian Council of Trade Unions, Geoff Fary, said regulations that take into account the unique properties of nano-sized materials were urgently needed to protect the health and safety of workers and consumers. “With animal tests showing some nano-materials share the same characteristics and reactions as asbestos fibres, governments and business must not repeat the painful lessons of the past and allow another tragedy to occur.”
Little was known about the use of nano-materials in Australia and a registry of all companies and organisations manufacturing, importing and supplying products containing them should be established, he said.
Issues of concern in workplaces included skin exposure and inhalation of droplets of nano-material. “Until we know more â€¦ we should regulate as if it is dangerous to human health. It is the only safe option.”
Britain's Royal Society recommended in 2004 that products containing nano-ingredients face rigorous safety testing and be labelled before sale. No country has yet introduced nano-specific regulations, but last month the European Parliament recommended stringent new rules for safety assessment and labelling of nano-ingredients in food although it will not become law until national governments agree to the directive.
Scientists say much more money needs to be spent on safety research. Not enough is known, for example, about how to detect and trace nanoparticles in the body, said Dr Maxine McCall of CSIRO. “Right now we don't have sufficient information to have sensible regulation,” she told a recent forum on the issue in Canberra.
An OECD project has been established to develop safety tests for 14 priority nanoparticles but will take several years to complete. And the issue is complicated by the fact that the many thousands of different nanoparticles can have different possible toxicities, depending on their size, shape and how they are bound to other materials.
Last October a NSW parliamentary inquiry recommended that nano-versions of existing chemicals be assessed as new chemicals and nanoparticles in the workplace and in foods, sunscreens and cosmetics be labelled, but said regulations would be most effective if applied nationally.
A review for the Federal Government concluded last year there was no need for major changes to existing regulatory frameworks to cover new nano-materials.