By Olga Naidenko
After lead, asbestos, aromatic amine dyes, Minamata disease, Bhopal, and fluorochemicals, we presumably have learned something about worker safety, especially when it comes to large-scale production in cutting-edge chemical industries. So here comes the test: can we use this knowledge to ensure worker safety in the up-and-coming nanotechnology industry?
An international survey published in the May issue of Environmental Science and Technology addressed precisely this question: are nanomaterials firms and laboratories installing adequate, nano-specific environmental health and safety (EHS) programs, engineering controls, personal protective equipment, exposure monitoring and product stewardship programs?
The UC Santa Barbara researchers conducted a study of nano-EHS practices at 82 organizations across all geographical regions that worked with diverse types of nanomaterials, such as carbon nanotubes, fullerenes, quantum dots, nanowires and polymers in form of powders and dispersions. The results of the survey can be summarized in two telling sentences:
Workplace monitoring and nanospecific waste disposal were uneven and were only associated with the subset of organizations believing in special risks. A majority of organizations expressed a need for more toxicological information and EHS guidance.
On a reassuring note, many key stakeholders in the US and internationally are interested in developing guidelines for safe occupational handling approaches for nanomaterials. An earlier report by the Santa Barbara group documented on-going nanotechnology safety research and practical recommendations offered by NIOSH, EPA, Germany’s Federal Institute for Occupational Safety and Health, Japan’s National Institute of Advanced Industrial Science and Technology, and the UK Department for Environment, Food and Rural Affairs, as well as multiple academic, industrial, and non-governmental organizations.
Most importantly, in 2005 NIOSH drafted the document Approaches to Safe Nanotechnology, which identified the list of health concerns associated with nano-workplace:
- The potential for nanomaterials to enter the body is among several factors that scientists examine in determining whether such materials may pose an occupational health hazard. Nanomaterials have the greatest potential to enter the body if they are in the form of nanoparticles, agglomerates of nanoparticles, and particles from nanostructured materials that become airborne or come into contact with the skin.
- Based on results from human and animal studies, nanoparticles can be inhaled and deposit in the respiratory tract; and based on animal studies, airborne nanomaterials can enter the blood stream, and translocate to other organs.
- Experimental studies in rats have shown that equivalent mass doses of insoluble ultrafine particles (smaller than 100 nm) are more potent than large particles of similar composition in causing pulmonary inflammation and lung tumors in those laboratory animals. However, toxicity may be mitigated by surface characteristics and other factors. Results from in vitro cell culture studies with similar materials are generally supportive of the biological responses observed in animals.
- Cytotoxicity and experimental animal studies have shown that changes in the chemical composition, structure of the molecules, or surfaces properties of certain nanomaterials can influence their potential toxicity.
- Studies in workers exposed to aerosols of manufactured microscopic (fine) and nanoscale (ultrafine) particles have reported lung function decrements and adverse respiratory symptoms; however, uncertainty exists about the role of ultrafine particles relative to other airborne contaminants (e.g., chemicals, fine particles) in these work environments in causing adverse health effects.
- Engineered nanoparticles whose physical and chemical characteristics are like those of ultrafine particles need to be studied to determine if they pose health risks similar to those that have been associated with the ultrafine particles.
Perhaps some of these health concerns sound familiar. In fact, a number of scientists already expressed a concern that if appropriate precautionary measures are not taken, nano-materials in the workplace may become the new asbestos.
One cannot help but hope – surely we now know more and can do better than that? Meanwhile, here is the current state of nanotechnology safety, as reported from the survey:
Organizations overwhelmingly reported the lack of information and best-practice guidance from industry and governments as impeding their efforts in nanospecific EHS… 68% of organizations reported not monitoring the workplace for nanoparticles… There were numerous reports of apparently inadequate engineering controls, including specifying practices to protect samples rather than workers, turning off fume hood fans when handling nanopowders, and infrequently using HEPA exhaust filtration systems. Systematic examination of engineering controls for preventing exposure to engineered nanoparticles is in its early stages… Most respondents reported adhering to conventional waste disposal practices rather than considering nanospecific characteristics… Most of the surveyed organizations reported providing some form of guidance, mainly MSDS, for the safe use, but not safe disposal, of their products containing nanomaterials. Yet, standard MSDS do not address nanomaterials characteristics and would have to be modified to effectively communicate nanospecific information related to safety and product stewardship… Organizations worldwide are not in consensus regarding the existence of risks that would justify special attention to nanomaterials EHS… The general lack of end-of-life guidance for handling nanomaterials suggests the need for a common understanding of best practices regarding product stewardship.
So at present, the picture is mixed. As described in the survey,some nano-companies are aware of risks associated with nanomaterials. However, reported workplace practices “were primarily based on either conventional chemical hygience criteria, such as chemical compatibility, or cost factors.” Suposedly nano-specific EHS recommendations described by survey respondents did not appear sufficiently protective or reassuring. For example,
Employees [are recommended to] wear a disposable, typically plastic, body covering over their work clothes during high exposure activities and wear long gloves pulled over sleeves to minimize wrist exposure. Other recommendations included antistatic shoes to prevent ignition by static charges, sticky mats at laboratory entrances to prevent accidental nanomaterial transfers, and one organization reported advising employees who inhaled nanoparticles to consume milk and unrefined sugar as a prophylactic against toxic effects of fine particulates.
That’s a joke about milk and sugar, right? Nothing against these two – they go great with chocolate chip cookies – but hardly a satisfactory approach to deal with uncertain nano-chemical hazards that target lungs and can be also dermally absorbed.
A clear conclusion emerges from the survey: guidelines and regulations from governmental agencies are urgently needed so as to steer the nascent nanotech industry towards safe workplace practices. Hopefully, these necessary guidelines will be able to catch up with what appears to be an imminent nano-boom. Meanwhile, the question of the end-of-life for nano-products and materials will likely continue to loom large. And, as reported by the survey, this aspect of nano-safety is not well understood or addressed in the industry. That will be the question for government agencies like the EPA and environmentalists worldwide to tackle.
Olga Naidenko is a Senior Scientist at the Environmental Working Group (Washington, DC); she holds a PhD degree in immunology from the UCLA Molecular Biology Institute. Prior to joining EWG, she worked in Los Angeles, San Diego, and St. Louis, conducting research in molecular and structural immunology. At EWG, Olga focuses on human health effects of chemical pollution.