De minimis curat lex: New Zealand law and the challenge of the very small

In 2010, the New Zealand Government commissioned a review on the ability of New Zealand's regulatory systems to manage the potential health, safety and environmental risks posed by manufactured nanomaterials. Whilst some of the gaps identified by this review are specific to New Zealand's regulatory arrangements, other potential gaps are common to regulators in different jurisdictions. Scientific uncertainties about hazard, human exposure, nano-toxicity and risk persist. Regulators charged with protecting public health face challenges due to these scientific gaps. Deciding what burden and standard of proof is most appropriate in the face of uncertain scientific evidence is a common challenge. In light of this particular shared regulatory challenge, this article examines New Zealand's regulatory framework for hazardous substances. It will consider a range of potential regulatory challenges and 'gaps'. Specifically, it will explore the uncertainty surrounding standard of proof, for example, in the designation of 'hazardous' in New Zealand's Hazardous Substances and New Organisms Act 1996 . It will also explore the question of how 'precautionary' approach should be adopted in relation to hazardous substances containing nanoparticles, using carbon nanotubes as a topical and paradigmatic case study. Regulatory enforcement and compliance issues are also examined. Like other jurisdictions, New Zealand is no stranger to the difficulties posed by regulatory notification requirements which are not adhered to and for which there are no mechanisms in place for monitoring compliance.