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

The commercial exploitation of nanotechnology has attracted marked public interest since around the year 2000. Workers, including researchers and their students, were the first people exposed to the products of this new technology. If nanotechnology was to be responsibly developed, workers had to be protected (Schulte and Salamanca-Buentello 2006). The concern that engineered nanomaterials (ENMs) could be hazardous stemmed from awareness of the respiratory and cardiovascular effects of ultrafine air pollutants; industrial experience with health effects from welding fumes, and diesel particles, including metal fume fever; acute pulmonary inflammation from fumed silica; and various animal studies showing translocation of gold nanoparticles from nasal mucosa to the brain (De Lorenzo 1970) and respiratory effects due to ultrafine zinc (Amdur et al. 1988). Ultrafine particles were found to have greater pulmonary toxicity than larger respirable (fine) particles when measured by the mass dose; particle volume and particle surface area were found to be more predictive dose metrics (Morrow 1988; Oberdörster and Yu 1990; Duffin et al. 2002). Scientific literature on occupational exposures to and health effects from existing aerosol particulates and fibers provided a basis for evaluating the potential hazards of new nanoscale aerosols and highlighted gaps in the current body of knowledge (Maynard and Kuempel 2005).

Caution was initially sounded in 2000, when the United States National Science Foundation stated, “As currently envisioned, nanomaterials are likely to possess at least three properties that will generate novel safety and governance challenges: invisibility, micro-locomotion, and self-replication” (Roco and Bainbridge 2001). In 2004, the insurance company Swiss Re was more explicit, stating: “Presumably, nanoparticles must be handled with the same care given to bio-organisms or radioactive substances” (Hett 2004). In that same year, The Royal Society and The Royal Academy of Engineering warned, “There are uncertainties about the risk of nanoparticulates currently in production that need to be addressed immediately to safeguard workers and consumers and support regulatory decisions. … The evidence that has been reviewed suggests that manufactured nanoparticles and nanotubes are likely to be more toxic per unit mass than particles of the same chemical at larger size and will, therefore, present a greater hazard.… Free particles in the nanometer size range do raise health, environmental, and safety concerns, and their toxicology cannot be inferred from that of particles of the same chemical at larger size” (The Royal Society and The Royal Academy of Engineering 2004).

In 2004, when scientists from various countries met in Buxton, UK, for the first in a special series of nanotechnology occupational and environmental health (NanOEH) conferences of the occupational and environmental communities (Fig. 1), there were already over 200 claimed products identified as “nano-enabled” in commerce, indicating that workers were handling nanomaterials (Woodrow Wilson Center 2013). Moreover, the global market for nanomaterials was predicted to grow to an estimated $4.4 trillion by 2018 (Lux Research Inc. 2014). This meant that scientists and government officials had to answer not only whether the material was harmful, but also whether there were exposure and risk, and simultaneously, they had to devise strategies for handling nanomaterials safely. These NanOEH conferences represented periodic ad-hoc gatherings of the occupational safety and health community to address potential hazards of a new technology. They served to stimulate networking and discussion of emerging findings and needs in nanosafety research.

After almost two decades of commercial activity, it is worth assessing whether progress has been made on the critical issues of occupational safety and health in nanotechnology. In this article, we examine the history of the occupational safety and health efforts regarding ENMs from 2000 to 2015. To better explore progress in this field, eight important topical areas are distinguished: toxicology, metrology, exposure assessment, engineering controls and protective equipment, risk assessment, risk management, medical surveillance, and epidemiology. For each topical area, major milestones have been identified, including significant technical or research achievements as well as policy recommendation or adoption by national agencies, international government organizations, or professional non-governmental organizations. The selection of these milestones is based on the experience and judgment of the authors and includes consideration of the import assigned to actions and works by professional communities, as well as the volume of citations (as indicated by Google Scholar, Assessed August–September 2015) for academic literature. The selected milestones are then synthesized into timelines to allow a historical portrayal of critical findings and actions that have advanced knowledge in that area. Although this is a qualitative approach, this method provides a better context than would be available by a strictly quantitative review of the academic literature. Moreover, it allows one to more readily see not only how the field came to reach its current state, but also the current tasks and challenges in each area that remain to be addressed.