Researchers led by Professor Kenneth Donaldson at the University of Edinburgh examined the potential for long and short carbon nanotubes, long and short asbestos fibers and carbon black to cause pathological responses known as precursors of mesothelioma. The materials were injected into the abdominal cavity of mice -- a sensitive predictor of long fiber response in the lung lining.

Mesothelioma is a cancer of the lung lining that can take 30-40 years to appear following exposure, scientists said.

"The results were clear," said Donaldson. "Long, thin carbon nanotubes showed the same effects as long, thin asbestos fibers."

Asbestos fibers, he said, are harmful because they are thin enough to penetrate deep into the lungs, but sufficiently long to confound the lungs' mechanisms for getting rid of the particles.

The research is detailed in the journal Nature Nanotechnology