Unfortunately, there currently is not a site or an authority that you can go to and find the proper methods for handling nanomaterials. We don’t know the properties of the materials throughout the size ranges to be able to develop a specific directions for handling each different material. The Compact Fluorescent Light Bulbs (CFLs), which contain micrograms of mercury, have an Environmental Protection Agency (EPA) procedure for cleaning up the residue of a broken light (http://www2.epa.gov/cfl/cleaning-broken-cfl). The procedure starts with having people and pets leave the area. What do we do with nanomaterials?
Are nanomaterials more dangerous than CFLs? or less dangerous? In the vast majority of cases we don’t know. There has been initial efforts undertaken. OHSA awarded Rice University a contract to develop a short course on nanotechnology safety. This 8 hour course is available on the OSHA web site. In January 2013, NSF awarded Texas State University a contract to develop two courses (Introduction and Advanced) on nanotechnology safety education. The first roll out to students was started in Summer 2013. Modules from the courses are being evaluated during the Fall semester. More will be discussed on this effort in future blogs.
This takes us back to the question of “How do we handle nanomaterials?” First, let’s start with different categories of potential dangers. We will cover the handling issues in future blogs.
The first consideration is Toxicity Issues. Are there any known issues regarding the material under investigation/application? If there are, then existing procedures must be followed. One can not assume that a change in size reduces the toxicity. If Chemical Dangers are present, the established precautions must be followed. There are certain materials that have a high probability of Fire dangers. Others have concern about Explosion possibilities, which also ties into concern about Dust. Supposedly benign materials like flour can create an explosive environment if sufficient dust becomes airborne. Dust has additional hazards due to the ability to ingest the dust, which can aggregate in lungs or other parts of the body. Electrostatic issues are of a concern due to the fact that particles can cling to the researcher without his/her being aware and cause contamination outside the controlled environment.
There are other considerations that impact the approach to handling various materials. The Volume of the material is an important consideration as well as its Density. The Concentration of the material also fits into the considerations for the appropriate means of handling it. There are concerns that the Shape of the material will impact its ability to enter the human body. Straight shaped materials have the ability to more readily enter into a person’s body than Curved material. The fact that carbon nanotubes are needle-shaped, which is similar to asbestos, has raised concerns about the applications of the nanotubes. As a free floating “dust” there could be significant issues. Curved materials have a harder task in getting through some of the body’s defenses and are of somewhat less concern. The last item in today’s list is Size. There are some materials that have different shape characteristics depending on whether they are < 8nm, 8 to 20nm, or >20nm. One can not assume that the nanomaterials will keep the same structure as the size changes.
So what does one do? One method, which is reasonable safe, is to treat all materials as potentially dangerous until proven otherwise. In the evaluation of the potential dangers, one must consider all aspects of the material’s known properties and any proven properties of the nanomaterial. We will have more comments on this in the next few weeks.