Category: Asbestos

imagesThe National Institute of Standards and Technology (NIST) has issued what is being touted as the world’s first reference material for single-wall carbon nanotube soot.  In its statement, NIST calls single-wall carbon nanotubes (SWCNT) “perhaps the archetype of all nanoscale materials.”  The promise of SWCNT in industrial use is great (NIST chemical engineer Jeffrey Fagan stated that “full development of these materials should enable lighter, stronger materials, as well as improve many technologies from sensors to electronics and batteries”).  But as with most things, there’s a catch.

Production of SWCNT involves a complex process that is known for inconsistent quality, variability from batch to batch, and significant resulting impurities.  NIST has sought to provide the first standardized guidelines – both chemical and metric – to the production of nanotubes, through the publication of its Standard Reference Material SRM 2483 – Single-Wall Carbon Nanotubes (Raw Soot) on December 20, 2011.  The purpose of the SRM is to provide industrial developers and producers with a means to evaluate chemical and instrumental methods of analysis of carbon nanotubes with the goal of improving quality and consistency across the board.

Of special interest to me is the Material Safety Data Sheet (MSDS) for SWCNT raw soot, which was simultaneously issued by NIST.  The MSDS reveals that little is known about the potential hazards of this substance in the workplace setting.  The MSDS contains the following statement regarding single-wall carbon nanotubes raw soot:

“According to NIOSH, currently there are no studies reported in the literature of adverse health effects in workers producing or using carbon nanotubes or carbon nanofibers.  The concern about worker exposure to these materials arises from results of animal studies.  Several studies in rodents have shown an equal or greater potency of carbon nanotubes compared to other inhaled particles known to be hazardous to exposed workers (ultrafine carbon black, crystalline silica, and asbestos) in causing adverse lung effects including pulmonary inflammation and fibrosis.”

Did the word “asbestos” jump off the page?  And just because this substance is not listed as a potential carcinogen in the National Toxicology Program (NTP) Report on Carcinogens, the International Agency for Research on Cancer (IARC) Monographs, or by OSHA does not mean that it doesn’t pose a significant health risk to workers.  Pulmonary fibrosis, in the form of asbestosis and silicosis, has been a major public health problem for decades and a legal problem of immeasurable proportions.

Furthermore, the MSDS states, under Toxicology Information, that “[a]nimal in vitro cell studies have shown that SWCNT can cause genotoxicity and abnormal chromosome number due to interference with mitosis.”  But the research has not yet demonstrated any effects in the animals other than the observed impact, perhaps because the technology is so new and the research in its infancy.

Under Ecotoxicity Data, the MSDS states, “No data available.”

Clearly, there is an urgent need for more study of the potential health hazards of SWCNT, both acute and chronic.  So while the Standard Reference Material is a giant step toward consistency of standards, the MSDS reveals that it is only a baby step in the larger scheme of things.  Much research needs to be done on the impact of these new technologies on workers and ultimately on consumers and the environment.

The NIST statement, with image, is available at

The Standard Reference Material is available at

The MSDS, with sources, is available through a link from the Standard Reference Material page immediately above.

asbestos-fibreI have written here about various ways in which nanomaterials may be comparable to asbestos – both in the ways nanoparticles may impact the human body and the ways the law may respond.  So it’s not surprising that one more comparison has emerged recently.

 Scientists from Brown University have studied the impact of carbon nanotubes on mouse cells.  Their study, published in the September 19, 2011 issue of Nature Nanotechnology, showed that certain types of multi-walled carbon nanotubes enter cells in a way that causes an immune response and cellular inflammation.  The physical properties of the nanotubes are responsible for this reaction.  As the researchers stated in their abstract, “cylindrical one-dimensional nanomaterials such as carbon nanotubes enter cells through the tip first.”  Certain nanotubes – those with end caps or carbon shells at their tips – seem to trigger the inflammatory reaction.  The researchers mention asbestos fibers in their abstract as being analogous (though they are clearly physically different) in this important aspect.

Does this mean that carbon nanotubes will create the same health problems that asbestos created?  Not necessarily.  Some might consider asbestos-related illness to be one of the major scourges of the last quarter of the 20th Century and well beyond.  Asbestos has shaped the law in relation to workplace safety and mass tort litigation, and has transformed industry.  Asbestos is a naturally occurring substance, and its use has been limited since the 1970s.  Its health effects, however, are ongoing because symptoms of asbestos-related disease typically occur after a latency period that may be quite long.

Nanomaterials, however, are engineered and represent new technology in a new technological world.  A new response is warranted.  What can be done going forward?  Scientists may be able to engineer carbon nanotubes in a way that will eliminate this particular inflammatory response.  But more research needs to be done before that.  For example, these same researchers intend to study whether nanotubes with others types of tips create the same or similar cellular response.

For now, we may be heading in the direction of “intelligent tip modification,” as the researchers refer to it.  Let’s hope we aren’t headed down the asbestos road again.


The abstract of the article may be accessed at


For a report on the Brown University study, see the following piece in the BNA subscription service:

Greg Hellman, Researchers Show How Carbon Nanotubes Pierce Cells, Leading to Inflammation, 18 Daily Env’t Rep. (BNA) A-12 (Sept. 20, 2011).

asbestos-fibreEarlier, I wrote about some potential similarities between asbestos personal injury litigation and the litigation that is certain to come over nanoparticles and human health.  I will be writing on and off about this topic going forward as well.  I can’t emphasize enough the urgency of avoiding another disaster like asbestos litigation, which has clogged the courts since the 1970s.

For example, engineered nanomaterials are being placed into building materials.  In the first instance, these materials are being designed and manufactured in the primary workplace environment, thus potentially exposing workers to hazards about which little or nothing is known.  Another set of workers, those using the building materials in the secondary workplace, run the risk of exposure to potentially harmful substances.

The history of asbestos shows that the early studies were conducted on asbestos textile factory workers, but that meaningful studies on workers out in the field who were installing the materials lagged far behind.  Then, when the studies began to raise danger signals, the industry ignored those signals until the specter of mass litigation and government regulation forced recognition.  By then it was too late.

Nanomaterials present some of the same workplace issues, particularly when used in building materials.  The hazards of the primary workplace may be different from those in the secondary workplace.  Studies must be conducted on both types of environments.

Further, there is a third concern, which also mirrors the asbestos experience.  At some point down the line (years or decades), the anticipated life of the materials will expire, just as asbestos insulation materials have done.  At that point, degeneration of the materials could put nanomaterials into the environment to a degree that could endanger the safety of persons in the vicinity.

In the case of nanomaterials, do we know any of this for certain?  No.  But at the present time we know almost nothing about any of these safety issues.  In December, the National Institute for Occupational Safety and Health (NIOSH) proposed a workplace exposure limit for carbon nanotubes and nanofibers.  This is a start; but without hard data, it is really only a guess.  And it is not necessarily consistent with limits for other substances.

While the industries creating and using nanomaterials will likely take seriously the lessons of asbestos, more should be done up front to ascertain the seriousness and scope of the hazards that the materials may present.  Now is the time.  If the hazards outrun the studies, the finish line will be litigation.