III. Health and Safety of the Public and Workers
Adequate and effective nanomaterial oversight requires an immediate emphasis on preventing known and potential exposures to nanomaterials that have not been proven safe. This is essential for both the public and nano-industry workers because some materials present potential hazards and others are largely untested. Free nanoparticles (nanomaterials that are not bound up in other materials) are of particular concern because they appear most likely to enter the body, react with cells, and cause tissue damage.[18] Embedded nanoparticles also pose exposure concerns. Workers may be exposed to such materials throughout the manufacturing process, while disposal and recycling activities may expose the public and the environment.
Due to their size, nanoparticles can cross biological membranes, cells, tissues, and organs more readily than larger particles.[19] When inhaled, they can go from the lungs into the blood system.[20] There is growing evidence that some nanomaterials may penetrate intact skin,[21] especially in the presence of surfactants[22] or massaging or flexing of the skin,[23] and gain access to systemic circulation.[24] When ingested, nanomaterials may pass through the gut wall and into the blood circulation.[25] Once in the blood stream, nanomaterials can circulate throughout the body and can lodge in organs and tissues including the brain, liver, heart, kidneys, spleen, bone marrow, and nervous system.[26] Once inside cells, they may interfere with normal cellular function, cause oxidative damage and even cell death.[27]
Inadequate funding and the lack of a governmental emphasis on human health risk research enabled the current situation in which some people are exposed to manufactured nanomaterials daily despite a dearth of data on potential long-term or chronic effects of those materials.[28] The people that research, develop, manufacture, package, handle, transport, use and dispose of nanomaterials will be those most exposed and therefore most likely to suffer any potential human health harms. As such, worker protection should be paramount within any nanomaterial oversight regime. The U.S. National Science Foundation estimates that by 2015 nanotechnology industries will employ two million workers globally.[29] In addition, many researchers and students work with nanomaterials in academic laboratories. Despite the burgeoning nano-workforce, no existing occupational safety and health standard specifically addresses nanotechnologies and nanomaterials, and there are no accepted standard methods for measuring human exposure to nanomaterials in the workplace.
Any regulatory regime designed to protect workers from the health effects of nanomaterials requires written comprehensive safety and health programs addressing workplace nanotechnology issues. Employers should use the precautionary principle as the basis for implementing protective measures for assuring the health and safety of workers. The hierarchy of exposure controls—elimination, substitution, engineering controls, work practice/administrative approaches, and personal protective equipment—should be employed. Exposure monitoring, medical surveillance and worker training are necessary to ensure that workers receive the most up-to-date information on nanomaterials. Workers and their representatives should be involved in all aspects of workplace nanotechnology safety and health issues without fear of retaliation or discrimination. Finally, existing occupational, safety and health standards must be scrutinized for their applicability to nanomaterials.[30]
18 See, e.g., The Royal Society and the Royal Academy of Engineering, Nanoscience and nanotechnologies: Opportunities and uncertainties 36, 79-80 (2004); Oberdörster et al., Principles for Characterizing the Potential Human Health Effects From Exposure to Nanomaterials: Elements of a Screening Strategy, 2 Particle and Fibre Toxicology 8, 29 (2005).
19 See, e.g., Holsapple et al., Research Strategies for Safety Evaluation of Nanomaterials, Part II: Toxicological and Safety Evaluation of Nanomaterials, Current Challenges and Data Needs, 88 Toxicological Sciences 12 (2005).
21 Monteiro-Riviere N. et al., Penetration of Intact Skin by Quantum Dots with Diverse Physicochemical Properties, 91 Toxicological Sciences 159 (2006); Rouse J et al., Effects of Mechanical Flexion on the Penetration of Fullerene Amino Acid-Derivatized Peptide Nanoparticles through Skin, 7(1) Nano Letters 155 (2007).
22 Monteiro-Riviere N. et al., Skin Penetration of Fullerene Substituted Amino Acids and their Interactions with Human Epidermal Keratinocytes, 827 The Toxicologist 168 (2006).
23 R ouse J. et al., Effects of Mechanical Flexion on the Penetration of Fullerene Amino Acid- Derivatized Peptide Nanoparticles through Skin, 7(1) Nano Letters 155 (2007).
24 Toll R. et al., Penetration Profile of Microspheres in Follicular Targeting of Terminal Hair Follicles, 123 The Journal of Investigative Dermatology, 168 (2004).
25 Florence A. et al., Transcytosis of Nanoparticle and Dendrimers Delivery Systems: Evolving Vistas, 50 Adv Drug Deliv Rev S69 (2001); Hussain N. et al., Recent Advances in the Understanding of Uptake of Microparticulates Across the Gastrointestinal Lymphatics, 50 Adv Drug Deliv Rev 107 (2001); Hillyer J. F. et al., Gastrointestinal persorption and tissue distribution of differently sized colloidal gold nanoparticles, 90 J Pharm Sci 1927-1936 (2001).
26 See, e.g., Oberdörster et al., Nanotoxicology: An Emerging Discipline From Studies of Ultrafine Particles, 113 Environmental Health Perspectives 823-839 (2005).
27 Borm PJ, Kreyling, W, Toxicological hazards of inhaled nanoparticles--potential implications for drug delivery, 4 J Nanosci Nanotechnol 521-531 (2004).
28 See, e.g., Rick Weiss, Nanotechnology Risks Unknown; Insufficient Attention Paid to Potential Dangers, Report Says, Wash. Post, Sept. 26, 2006, at A12.
29 See, e.g., Mihail C. Roco, Nanotechnology’s Future, Scientific American, Aug. 2006.
30 See Occupational Safety and Health Act (OSHA) standards (29 CFR). Specific attention should be given to Hazard Communication (1910.1200), Respiratory Protection (1910.134), Personal Protective Equipment (1910.132), Access to Medical And Exposure Records (1910.1020), Hazardous Chemicals in Laboratories (1910.1450), and Chemical-specific standards where applicable (1910, Subpart Z).