National nanotechnology partnership to protect workers

Nanotechnology is predicted to improve many aspects of human life. By 2015, it is estimated to represent $3.1 trillion in manufactured goods. Data is emerging that exposure to nanomaterials may pose a health risk to workers. If the economic promise of nanotechnology is to be achieved, ways need to be found to protect nanotechnology workers now. The Occupational Safety and Health Act of 1970 (OSHAct) gave the responsibility to protect workers to the Occupational Safety and Health Administration (OSHA) and the National Institute for Occupational Safety and Health (NIOSH) through research, standards adoption, and standards enforcement. Since 1980, adopting new occupational health standards has grown more complex. The increased complexity has greatly slowed efforts to adopt protective standards for toxic agents that are well-known to pose significant risks. The likelihood of rapidly adopting standards to protect workers from nanomaterials, whose risks are just emerging, seems even more unlikely. Use of the OSHAct’s general duty clause to protect workers also seems uncertain at this time. In the interim, a national partnership led by NIOSH involving nanotech manufacturers and downstream users, workers, academic researchers, safety, and health practitioners is proposed. A National Nanotechnology Partnership would generate knowledge about the nature and the extent of worker risk, utilize that knowledge to develop risk control strategies to protect nanotechnology workers now, and provide an evidence base for NIOSH recommendations to OSHA for a nanotechnology program standard at a future date.     

Airborne Nanostructured Particles and Occupational Health

Nanotechnology is leading to the development in many field, of new materials and devices in many fields that demonstrate nanostructure-dependent properties. However, concern has been expressed that these same properties may present unique challenges to addressing potential health impact. Airborne particles associated with engineered nanomaterials are of particular concern, as they can readily enter the body through inhalation. Research into the potential occupational health risks associated with inhaling engineered nanostructured particles is just beginning. However, there is a large body of data on occupational and environmental aerosols, which is applicable to developing an initial assessment of potential risk and risk reduction strategies. Epidemiological and pathological studies of occupational and environmental exposures to airborne particles and fibers provide information on the aerosol-related lung diseases and conditions that have been observed in humans. Toxicological studies provide information on the specific disease mechanisms, dose–response relationships, and the particle characteristics that influence toxicity, including the size, surface area, chemistry or reactivity, solubility, and shape. Potential health risk will depend on the magnitude and nature of exposures to airborne nanostructured particles, and on the release, dispersion, transformation and control of materials in the workplace. Aerosol control methods have not been well-characterized for nanometer diameter particles, although theory and limited experimental data indicate that conventional ventilation, engineering control and filtration approaches should be applicable in many situations. Current information supports the development of preliminary guiding principles on working with engineered nanomaterials. However critical research questions remain to be answered before the potential health risk of airborne nanostructured particles in the workplace can be fully addressed. Disclaimer The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health     

Distinguishing nanomaterial particles from background airborne particulate matter for quantitative exposure assessment

As the production of engineered nanomaterials quantitatively expands, the chance that workers involved in the manufacturing process will be exposed to nanoparticles also increases. A risk management system is needed for workplaces in the nanomaterial industry based on the precautionary principle. One of the problems in the risk management system is difficulty of exposure assessment. In this article, examples of exposure assessment in nanomaterial industries are reviewed with a focus on distinguishing engineered nanomaterial particles from background nanoparticles in workplace atmosphere. An approach by JNIOSH (Japan National Institute of Occupational Safety and Health) to quantitatively measure exposure to carbonaceous nanomaterials is also introduced. In addition to real-time measurements and qualitative analysis by electron microscopy, quantitative chemical analysis is necessary for quantitatively assessing exposure to nanomaterials. Chemical analysis is suitable for quantitative exposure measurement especially at facilities with high levels of background NPs.     

Measuring particle size-dependent physicochemical structure in airborne single walled carbon nanotube agglomerates

As-produced single-walled carbon nanotube (SWCNT) material is a complex matrix of carbon nanotubes, bundles of nanotubes (nanoropes), non-tubular carbon and metal catalyst nanoparticles. The pulmonary toxicity of material released during manufacture and handling will depend on the partitioning and arrangement of these components within airborne particles. To probe the physicochemical structure of airborne SWCNT aggregates, a new technique was developed and applied to aerosolized as-produced material. Differential Mobility Analysis-classified aggregates were analyzed using an Aerosol Particle Mass Monitor, and a structural parameter Γ (proportional to the square of particle mobility diameter, divided by APM voltage) derived. Using information on the constituent components of the SWCNT, modal values of Γ were estimated for specific particle compositions and structures, and compared against measured values. Measured modal values of Γ for 150 nm mobility diameter aggregates suggested they were primarily composed of non-tubular carbon from one batch of material, and thin nanoropes from a second batch of material – these findings were confirmed using Transmission Electron Microscopy. Measured modal values of Γ for 31 nm mobility diameter aggregates indicated that they were comprised predominantly of thin carbon nanoropes with associated nanometer-diameter metal catalyst particles; there was no indication that either catalyst particles or non-tubular carbon particles were being preferentially released into the air. These results indicate that the physicochemistry of aerosol particles released while handling as-produced SWCNT may vary significantly by particle size and production batch, and that evaluations of potential health hazards need to account for this. Disclaimer: The mention of any company or product does not constitute an endorsement by the Centers for Disease Control and Prevention. The findings and conclusions in this paper are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health.     

Horses for courses: risk information and decision making in the regulation of nanomaterials

Despite the widespread commercial use of nanomaterials, regulators currently have a limited ability to characterize and manage risks. There is a paucity of data available on the current production and use of nanomaterials and extreme scientific uncertainty on most aspects of the risk assessment “causal chain.” Regulatory decisions will need to be made in the near-term in the absence formal quantitative risk assessments. The article draws on examples from three different regulatory contexts—baseline data monitoring efforts of the U.S. Environmental Protection Agency and California Department of Toxic Substances Control, prioritization of risk information in the context of environmental releases, and mitigation of occupational risks—to argue for the use of decision-analytic tools in lieu of formal risk assessment to help regulatory bodies. We advocate a “horses for courses” approach whereby existing analytical tools (such as risk ranking, multi-criteria decision analysis, and “control banding” approaches) might be adapted to regulators’ goals in particular decision contexts. While efforts to build new and modify existing tools are underway, they need greater support from funding and regulatory agencies because innovative approaches are needed for the “extreme” uncertainty problems that nanomaterials pose.     

Governance implications of nanomaterials companies’ inconsistent risk perceptions and safety practices

Current research on the nanotechnology industry indicates its downstream expansion at a rapid pace, while toxicological research and best practices for environmental health and safety are still being developed. Companies that use and/or produce engineered nanomaterials (ENMs) have enormous potential to influence safe-handling practices for ENMs across the product life cycle. Knowledge of both industry practices and leaders’ perceptions of risk is vital for understanding how companies will act to control potential environmental and health risks. This article reports results from a new international survey of nanomaterials companies in 14 countries. In this survey, company participants reported relatively high levels of uncertainty and/or perceived risk with regard to ENMs. However, these perspectives were not accompanied by expected risk-avoidant practices or preferences for regulatory oversight. A majority of companies indicated “lack of information” as a significant impediment to implementing nano-specific safety practices, but they also reported practices that were inconsistent with widely available guidance. Additionally, in the absence of safe-handling regulations, companies reported nano-specific health and safety programs that were narrow in scope. Taken together, these findings indicate that health and safety guidance is not reaching industry. While industry leaders’ reluctance toward regulation might be expected, their own reported unsafe practices and recognition of possible risks suggest a more top-down approach from regulators is needed to protect workers and the environment.     

Leptokurtic portfolio theory

The question of optimal portfolio is addressed. The conventional Markowitz portfolio optimisation is discussed and the shortcomings due to non-Gaussian security returns are outlined. A method is proposed to minimise the likelihood of extreme non-Gaussian drawdowns of the portfolio value. The theory is called Leptokurtic, because it minimises the effects from “fat tails” of returns. The leptokurtic portfolio theory provides an optimal portfolio for investors, who define their risk-aversion as unwillingness to experience sharp drawdowns in asset prices. Two types of risks in asset returns are defined: a fluctuation risk, that has Gaussian distribution, and a drawdown risk, that deals with distribution tails. These risks are quantitatively measured by defining the “noise kernel” — an ellipsoidal cloud of points in the space of asset returns. The size of the ellipse is controlled with the threshold parameter: the larger the threshold parameter, the larger return are accepted for investors as normal fluctuations. The return vectors falling into the kernel are used for calculation of fluctuation risk. Analogously, the data points falling outside the kernel are used for the calculation of drawdown risks. As a result the portfolio optimisation problem becomes three-dimensional: in addition to the return, there are two types of risks involved. Optimal portfolio for drawdown-averse investors is the portfolio minimising variance outside the noise kernel. The theory has been tested with MSCI North America, Europe and Pacific total return stock indices.     

Survey of noise in coal preparation plants

In response to the continuing problem of noise induced hearing loss (NIHL) among mine workers, the National Institute for Occupational Safety and Health (NIOSH) has conducted numerous noise surveys in coal preparation plants. The research, consisting of worker dose monitoring, task observations, and equipment noise profiling, was completed in eight separate preparation plants. Worker dose monitoring was conducted for three shifts in most cases. Workers experiencing higher than allowable doses were task-observed for one full shift to correlate dose to noise source(s). Finally, noise levels on all floors, and in lunch rooms and control rooms, were characterized. Results indicate that only workers who routinely spend a significant portion of their shift in the plants (away from the control rooms) are susceptible to overexposure from noise. Certain pieces of equipment (screens, centrifuges, sieve bends) are the loudest primary noise sources responsible for the worker noise exposures.     

Designing oversight for nanomedicine research in human subjects: systematic analysis of exceptional oversight for emerging technologies

The basic procedures and rules for oversight of U.S. human subjects research have been in place since 1981. Certain types of human subjects research, however, have provoked creation of additional mechanisms and rules beyond the Department of Health & Human Services (DHHS) Common Rule and Food and Drug Administration (FDA) equivalent. Now another emerging domain of human subjects research—nanomedicine—is prompting calls for extra oversight. However, in 30 years of overseeing research on human beings, we have yet to specify what makes a domain of scientific research warrant extra oversight. This failure to systematically evaluate the need for extra measures, the type of extra measures appropriate for different challenges, and the usefulness of those measures hampers efforts to respond appropriately to emerging science such as nanomedicine. This article evaluates the history of extra oversight, extracting lessons for oversight of nanomedicine research in human beings. We argue that a confluence of factors supports the need for extra oversight, including heightened uncertainty regarding risks, fast-evolving science yielding complex and increasingly active materials, likelihood of research on vulnerable participants including cancer patients, and potential risks to others beyond the research participant. We suggest the essential elements of the extra oversight needed.     

A review of legislation on industrial noise

This paper commences by reviewing the 1961 Factories Act, which placed a duty on the employer to provide a safe place of work. This duty is reiterated in the 1974 Health and Safety at Work Bill (given the Royal Assent on 31 July 1974 and now an Act), and the Secretary of State for Employment is given power to make regulations which will make perfectly clear what the liability of the employer is. Legal requirements concerning the design and manufacture of articles for use at work are also made in the new Bill. They must be designed so as to be safe and without risk to health. Furthermore, it is the duty of the manufacturer to carry out any necessary research with a view to the discovery, and the elimination or minimisation, of any risks to health or safety which the article may afford.     

Risk perceptions starting to shift? U.S. citizens are forming opinions about nanotechnology

This article presents early results from an opinion formation study based on a 76-member panel of U.S. citizens, with comparison data from a group of 177 nanotechnology experts. While initially similar to the expert group in terms of their perceptions of the risks, benefits, and need for regulation characterizing several forms of nanotechnology, the first follow-up survey indicates that the panel is beginning to diverge from the experts, particularly with respect to perceptions of the levels of various “societal” risks that nanotechnology might present. The data suggest that responding to public concerns may involve more than attention to physical risks in areas such as health and environment; concerns about other forms of risk actually appear more salient.     

Evaluating the Control Banding Nanotool: a qualitative risk assessment method for controlling nanoparticle exposures

Control banding (CB) strategies offer simplified processes for controlling worker exposures in the absence of firm toxicological and exposure information. The nanotechnology industry is an excellent candidate for applying such strategies with overwhelming uncertainties of work-related health risks posed by nanomaterials. A recent survey shows that a majority of nanomaterial producers are not performing a basic risk assessment of their product in use. The CB Nanotool, used internationally, was developed to conduct qualitative risk assessments to control nanoparticle exposures. Nanotoxicology experts have requested standardization of toxicological parameters to ensure better utility and consistency of research. Such standardization would fit well in the CB Nanotool’s severity and probability risk matrix, therefore enhancing the protection of nanotechnology industry workers. This article further evaluates the CB Nanotool for structure, weighting of risk factors, and utility for exposure mitigation, and suggests improvements for the CB Nanotool and the research needed to bolster its effectiveness.     

Nanosafety practices: results from a national survey at research facilities

The exposure to engineered nanomaterials (ENMs) is a new emerging risk at work due to an increase in the number of workers potentially exposed to them and the current lack of data on their health and safety risks. This paper reports the findings of a survey designed to study the safety practices employed by workers in Spanish research facilities performing tasks involving the use of ENMs at research level. A questionnaire pretested and validated by an expert panel was sent by e-mail to the target audience. The 425 surveys completed show that most of the respondents handled up to 5 different ENMs, in suspension, in small amounts during short periods of exposure. The implementation of common hygienic practices, such as the use of protection for hands and the implementation of fume hoods, is widely indicated. The selection of the preventive and protective measures does not depend on the characteristics of ENMs handled. Also, the risks posed by ENMs are widely ignored. Besides the performance of risk assessment, hygienic monitoring and the conducting of a specific health surveillance are practically non-existent although some accidents relating to ENMs were identified. In conclusion, workers’ exposure to ENMs seems to be low. Even though the best practices and preventive and protective measures reported were employed, most of the respondents could not be correctly protected. Moreover, workers do not associate the measures implemented with the nanorisks. Finally, there is a lack of proactive action underway to protect the workers, and concerns about safety are weakly evidenced.     

On the role of interband surface plasmons in carbon nanotubes

We review the properties of collective surface excitations—excitons and interband plasmons—in single-walled and double-walled carbon nanotubes. We show that an electrostatic field applied perpendicular to the nanotube axis can control the exciton-plasmon coupling in individual small-diameter (≲nm) singlewalled nanotubes, both in the linear excitation regime and in the non-linear excitation regime with the photoinduced biexcitonic states formation. For double-walled carbon nanotubes, we report a profound effect of interband surface plasmons on the inter-tube Casimir force at tube separations similar to their equilibrium distances. Strong overlapping plasmon resonances from both tubes warrant their stronger attraction. Nanotube chiralities possessing such collective excitation features will result in forming the most favorable innerouter tube combination in double-walled carbon nanotubes. These findings pave the way for the development of new generation of tunable optoelectronic and nano-electromechanical device applications with carbon nanotubes.     

Kardar—Parisi—Zhang equation in one dimension and line ensembles

For suitably discretized versions of the Kardar—Parisi—Zhang equation in one space dimension, exact scaling functions are available, amongst them the stationary two-point function. We explain one central piece from the technology through which such results are obtained, namely the method of line ensembles with purely entropic repulsion.     

Taking stock of the occupational safety and health challenges of nanotechnology: 2000–2015

Engineered nanomaterials significantly entered commerce at the beginning of the 21st century. Concerns about serious potential health effects of nanomaterials were widespread. Now, approximately 15 years later, it is worthwhile to take stock of research and efforts to protect nanomaterial workers from potential risks of adverse health effects. This article provides and examines timelines for major functional areas (toxicology, metrology, exposure assessment, engineering controls and personal protective equipment, risk assessment, risk management, medical surveillance, and epidemiology) to identify significant contributions to worker safety and health. The occupational safety and health field has responded effectively to identify gaps in knowledge and practice, but further research is warranted and is described. There is now a greater, if imperfect, understanding of the mechanisms underlying nanoparticle toxicology, hazards to workers, and appropriate controls for nanomaterials, but unified analytical standards and exposure characterization methods are still lacking. The development of control-banding and similar strategies has compensated for incomplete data on exposure and risk, but it is unknown how widely such approaches are being adopted. Although the importance of epidemiologic studies and medical surveillance is recognized, implementation has been slowed by logistical issues. Responsible development of nanotechnology requires protection of workers at all stages of the technological life cycle. In each of the functional areas assessed, progress has been made, but more is required.     

Noise dosimeter for monitoring exposure to impulse noise

Commercially available noise dosimeters do not perform properly in impulsive noise environments because they suffer from instrumentation limitations and lack metrics that characterize impulse noise. In this paper, a design concept is proposed for an impulse noise monitoring dosimeter that addresses the current dosimeter’s limited capabilities and describes the various parameters that can appropriately be used to measure and evaluate exposure to impulse noise. The design concept is based on the accurate acquisition and storage of the original impulse waveform. For data analysis (using MATLAB) and calculation of “impulse noise metrics,” National Institute for Occupational Safety and Health (NIOSH) used a prototype impulse noise dosimeter system that consisted of a Bruel&Kjaer 4136 microphone and a Panasonic Digital Audio Tape Recorder. The proposed instrument would enable collection of data for validation of presently defined and yet to be defined metrics quantifying noise-induced permanent threshold shifts (NIPTS) resulting from impulse/impact exposures. It will also enable occupational safety and health professionals to make accurate measurements of ultimately approved metrics.     

Experimental study of the variation of the plasma temperature with the laser flux

Experiments performed with a 50 MW — 60 nsec ruby laser to estimate the temperature of the plasma produced on the planar targets of carbon as well as polyethylene are reported. Temperatures were estimated by two foil ratio technique. The temperatures of carbon and polyethylene plasma show aφ ^2/9 dependance on flux in the flux regime of 10¹⁰ W/cm² to 5 × 10¹¹ W/cm². The comparatively slower dependance is explained on the basis of purely collisional absorption, the effect being enhanced due to relatively long duration of the laser pulses. Scaling laws of plasma temperature against laser flux obtained by different workers in different flux regimes have been analysed on the basis of collisional and non-collisional absorption.     

Optimization of constrained composite absorbers using simulated annealing

Sound reverberation is an important problem in some industrial environments. As indicated by the Occupational Safety and Health Act of 1970, noise is responsible for the psychological and physiological ills of workers. Therefore reduction of reverberation becomes essential. For maintenance and other reasons, the thickness of sound absorbers used for reverberation control may be constrained. Consequently there is interest in minimizing noise using sound absorbers with constrained thickness. Optimization of a composite absorber using a simulated annealing algorithm is presented. Simulated annealing is a stochastic relaxation technique based on analogy with the physical process of annealing metal. The algorithm requires a mathematical model for the acoustical properties of the absorber. Before optimization, the accuracy of the mathematical model was checked against experimental data. A program for optimizing in respect of broad band noise at a specified receiver has been created and run. Results prove that SA optimization provides a quick and efficient approach in designing constrained thickness composite sound absorbers.