Edinburgh, Scotland – Longer nanofibers may be dangerous to workers because they can become lodged in the lung cavity, concludes a study conducted by the University of Edinburgh.

Researchers created fibers of different lengths and compared their effect on mouse cells. A clear threshold emerged – lung cells were not affected by short fibers measuring less than five-thousandths of a millimeter long, while longer fibers were able to cause disease, according to the study abstract.

The study was published in the August issue of the journal Toxicology Sciences.