On March 6, 2009, the United Kingdom (UK) Health and Safety Executive (HSE) published an information sheet on the risk management of carbon nanotubes (CNT). According to HSE, the information sheet “is specifically about the manufacture and manipulation of carbon nanotubes and has been prepared in response to emerging evidence about the toxicology of these materials. However, the risk management principles detailed here are equally applicable to other nanodimensioned bio-persistent fibres with a similar aspect ratio.” HSE cites as “new evidence” a recent study by the University of Edinburgh, which “found that long, straight [multi-walled CNTs] with a high aspect ratio produced a marked inflammatory reaction and the formation of granulomas when injected into the abdominal cavity of mice.”

HSE states:

HSE views CNTs as being substances of very high concern. Although the recent findings only apply to some CNTs, we think a precautionary approach should be taken to the risk management of all CNTs, unless sound documented evidence is available on the hazards from breathing in CNTs. If their use cannot be avoided, HSE expects a high level of control to be used.

The information sheet includes specific recommendations for risk management. According to the information sheet, waste CNTs “should be classified and coded as hazardous waste.”