Research conducted at the University of Texas at Dallas, United States, and funded by the Semiconductor Research Corporation (SRC), found that nanotubes may not be as toxic as previously reported elsewhere. Instead, contaminants mixed during the manufacture should be credited with the adverse health effects. According to Rockford Draper, a professor who worked on the study, “Carboxylated single-walled carbon nanotubes indeed reduce the ability of mammalian cells to grow in culture, but by using simple filtration methods we were able to remove the contaminants introduced during manufacturing. The resulting purified nanotubes were shown to have no ill effect on mammalian cells grown in culture.” Commercial manufacturers of nanotubes can immediately begin using the filtration process, and can then offer pre-screened purified nanotubes. Dan Herr, director of nanomanufacturing sciences at SRC, said, “During the manufacture of semiconductors using nanotubes, they are usually immobilized, preventing them from entering the environment. Nevertheless, we will continue to focus our efforts on minimizing their health impact and on insuring the safety of both the workers using these nanotube-based materials as well as on their potential hazards after manufacturing.”
http://www.eetimes.com/electronics-news/4217099/Carbon-nanotubes-not-toxic–researchers-say