New research shows that carbon nanotubes are shaped like asbestos and can encourage tumor growth, but further investigation is needed to determine whether they pose risks in humans, according to a report published Tuesday.

Nature Nanotechnology published findings from researchers from the United Kingdom and Washington, D.C., that showed mice injected with certain carbon nanotubes suffered inflammation and lesions that can -- but don't always -- lead to cancer.

"This is of considerable importance, because research and business communities continue to invest heavily in carbon nanotubes for a wide range of products under the assumption that they are no more hazardous than graphite," the researchers wrote. "Our results suggest the need for further research and great caution before introducing such products into the market if long-term harm is to be avoided."

The mice developed symptoms in their chest cavities after nanotubes were injected near their lungs. The latest research suggests that carbon nanotubes, with structure and length similar to asbestos fibers, could be toxic. However, researchers aren't sure whether nanotubes are likely to be inhaled and persist inside the body. Asbestos persists in the body after inhalation and can lead to lung cancer.

Carbon nanotubes are extremely strong and are useful in electrical circuits, drug delivery, and other applications. Their adoption had been slowed because of a lack of cost-effective means of mass production, but advances from private and public funding have sped up production and deployment of the technology.

Future findings could impact manufacturing plants, worker safety guidelines, and consumer warnings.