Specific lengths of the tiny fibres were found to cause "asbestos-like" inflammation and lesions in mice.
Use of asbestos triggered a pandemic of lung disease in the 20th Century.
There are high hopes for the tiny carbon molecules, which have remarkable properties that could be used for advanced electronics and materials.
They are already known to be incorporated into products such as tennis rackets, bicycle handlebars and baseball bats, where they are used because of their strength and light weight.
Other undocumented products may also make use of them, the researchers said, but companies did not have a duty to report their use.
"As a society, we cannot afford not to exploit this incredible material but neither can we afford to get it wrong - as we did with asbestos," said Dr Andrew Maynard of the Woodrow Wilson International Center for Scholars in Washington DC, US.
However, of the known goods there was "little risk" of exposure as the nanotubes are encased inside, the researchers said. But, they warned, there was a potential risk for workers exposed to the tubes during manufacturing and disposal.
Carbon nanotubes as dangerous as asbestos?
Posted on Thursday, May 22 2008 @ 00:01 CEST by Thomas De Maesschalck
So far little was known about the risks of carbon nanotubes but a new study suggests these fibres could trigger diseases similar to those caused by asbestos. BBC News reports long nanotubes caused inflammation and scar formation, similar to those caused by asbestos, when injected in mice.