By Dennis Draeger
Nanotechnologies offer a myriad of benefits and applications with more than 1300 nanotech-enabled consumer products from hair straighteners to cleaning fluids, but they also present several uncertainties and lack extensive regulation. As more products enabled by nanomaterials are released to the market, more workers risk exposure to potentially harmful materials—whether in a lab, a factory, or a construction site. Now, occupational safety and health agencies and researchers are providing more substantial guidance for handling nanomaterials at the workplace.
What is changing?
Researchers and government agencies from around the world are addressing the uncertainties in the work place in different ways. Some types of nanomaterials have been shown to be safe, but others have indicated potential for serious injury. Some agencies are providing guidance on a case by case basis depending on specific criteria for each type of nanomaterial while other agencies are advising a more broad safety measures for any nanomaterial to avoid even the slightest risks.
In the US this year, the Occupational Safety and Health Administration (OSHA) released a fact sheet entitled Working Safely with Nanomaterials. It offers a basic understanding of potential hazards associated with the broad and burgeoning field of nanotechnologies while specifying measures to minimize exposure in the workplace. The US National Institute for Occupational Safety and Health (NIOSH) has adopted a more specific approach by addressing each type of nanomaterial separately. Having released a final version of the Current Intelligence Bulletin (CIB) on Occupational Exposure to Titanium Dioxide in 2011, they are now working on a final version for a CIB on carbon nanotubes and nanofibers, and they recently released preliminary results of a study on a type of carbon nanotubes and their potential to cause cancer. Although this type of carbon nanotube does not cause cancer by itself, they stress the importance of their study within the occupational health community.
The UK has also released a general health and safety guidance for using nanomaterials at work which focuses on the manufacture and manipulation of nanomaterials in the workplace. However, a recent study by scientists in Switzerland and China shows that exposure to potentially harmful nanomaterials in the workplace can happen outside the laboratory or factory. Their report shows that polystyrene foam boards coated with a particular flame retardant release harmful nanoparticles when the foam is cut with a heated wire. The nanoparticles can be easily inhaled and transport the flame retardant which is toxic and will accumulate in the deepest part of the lungs where the most serious lung diseases often develop.
Having published their guidance a few years ago, Australia’s Safe Work Australia has recently released two reports which both present research into different safety concerns of nanoparticles and offer advice for controlling their risks. One looks at how composites made up of hazardous nanomaterials could present more danger when cutting them using an electrical saw or a band saw, but they say the proper use of conventional local exhaust ventilation reduces any risk. The second report finds that dust clouds with a high enough concentration of nanomaterials could cause an explosion if an ignition is also present, but they say most workplaces should already be practicing effective measures to reduce the threat of explosion when handling nanomaterials.
Why is this important?
Nanotechnologies have posed many uncertainties around public and environmental health, but those who work with nanomaterials are the first to be exposed. The field of nanotoxicology is moving slowly for a variety of reasons. Substances that are not toxic in their conventional state have been shown to be toxic at the nanometer level and nanoparticles with different characteristics such as chemical composition and morphology produce different results in toxicology studies. So it is possible for workers to be unnecessarily cautious when working with certain types of safe nanomaterials, but any substance can be toxic at a certain amount. Therefore the most important guideline for workers is exposure limits specific to the type and characterization—e.g. size, shape, surface area—of the nanomaterials they work with.
Although studies have established a plausible correlation between exposure to certain particles at the nanometer scale and symptoms shared by particular groups of people, especially small groups of workers at the same sites, nanomaterial exposure has not been shown definitively and conclusively to have caused human injury. While governments could enact more regulations on nanotechnologies, such measures would unduly postpone progress in medical research, among other benefits, with improved treatments for AIDS, cancer, Alzheimer’s, and many more diseases. The potential benefit of these treatments currently outweigh the plausible risks, but occupational guidelines for those who work with nanomaterials are a key step in helping society understand a nanotech-enabled market.