Scientists versus regulators: precaution, novelty & regulatory oversight as predictors of perceived risks of engineered nanomaterials

Abstract

Engineered nanoscale materials (ENMs) present a difficult challenge for risk assessors and regulators. Continuing uncertainty about the potential risks of ENMs means that expert opinion will play an important role in the design of policies to minimize harmful implications while supporting innovation. This research aims to shed light on the views of 'nano experts' to understand which nanomaterials or applications are regarded as more risky than others, to characterize the differences in risk perceptions between expert groups, and to evaluate the factors that drive these perceptions. Our analysis draws from a web-survey (N = 404) of three groups of US and Canadian experts: nano-scientists and engineers, nano-environmental health and safety scientists, and regulatory scientists and decision-makers. Significant differences in risk perceptions were found across expert groups; differences found to be driven by underlying attitudes and perceptions characteristic of each group. Nano-scientists and engineers at the upstream end of the nanomaterial life cycle perceived the lowest levels of risk, while those who are responsible for assessing and regulating risks at the downstream end perceived the greatest risk. Perceived novelty of nanomaterial risks, differing preferences for regulation (i.e. the use of precaution versus voluntary or market-based approaches), and perceptions of the risk of technologies in general predicted variation in experts' judgments of nanotechnology risks. Our findings underscore the importance of involving a diverse selection of experts, particularly those with expertise at different stages along the nanomaterial lifecycle, during policy development.

Figure 1. “Risk versus Benefit” ratings for nanotechnologies in general.

Color-coded bars indicate the proportion of respondents in each expert group (NSE, NEHS, and NREG) choosing the indicated response.

Figure 2. 'Risk Perception' ratings for NSE, NEHS, and NREG expert groups.

Mean scores for each group are indicated with points on respective color-coded lines capturing 14 different nanotechnology scenarios rated between ‘almost no risk’ and ‘high risk’. Significant differences in means were determined using a one-way ANOVA with post hoc analysis, and are indicated with a, b, and c markings as outlined in the legend.

Figure 3. Mean scores for the 'Novelty' and 'Attitudes toward Regulation' indices for NSE, NEHS, and NREG groups.

The continuum from ‘high’ to ‘low’ represents a factor score range of +/− 0.5, representing one half standard deviation in either direction from the index. a, b, and c markings indicate significant differences between groups, where a: NSE and NEHS, b: NSE and NREG, c: NEHS and NREG. Tukey HSD post hoc analysis confirms that differences in index scores are significant across all three groups for ‘Novelty’ (p<.05; NSE: N = 180, M = −0.29, SD = 0.86, NREG: N = 103, M = 0.39, SD = 0.88, NEHS: N = 121, M = 0.11, SD = 0.85), and for ‘Regulation: Preference for Precaution’ (p<.001; NSE: N = 180, M = −0.29, SD = 0.82; NEHS: N = 121, M = 0.06, SD = 0.93; NREG: N = 103, M = 0.43, SD = 0.81). Post hoc analysis confirmed a significant difference between NSE and NREG groups only for ‘Regulation: Market-Based, Voluntary’ (p<.022; NSE: N = 180, M = −0.08, SD = 0.80; NREG: N = 103, M = −0.21, SD = 0.91).

Figure 4. Comparison of perceptions of ‘novelty’ and ‘attitudes towards regulation’ across expert groups: a) Perceptions of the novelty of benefits versus novelty of risks. b) ‘Confidence in Markets and Voluntary Regulation’ versus ‘Preference for Precaution’.

* indicates significant difference in means between ‘novel risks’ and ‘novel benefits’ by paired t-test, where Novel Benefits M = 3.50, SD = 0.58, Novel Risks M = 2.89, SD = 0.65 for NSE group; Novel Benefits M = 3.3, SD = 0.62, Novel Risks M = 3.16, SD = 0.67, for NEHS group; and difference in means for NREG group is not significant.

Figure 5. Comparison of Tech Risk Index and Nano Risk Index scores by expert group.

Paired t-test scores confirmed a significant difference in means between Tech Risk Index and Nano Risk Index for the both the NREG group (Tech Risk Index M = −0.08, SD = 0.99; Nano Risk Index M = 0.26, SD = 0.90), and for the NSE group (Tech Risk Index M = −0.04, SD = 0.82; Nano Risk Index M = −0.20, SD = 0.84). * indicates significant difference in means between Tech Risk Index and Nano Risk Index scores.