Nanotechnology — engineering substances down to billionths of a metre in size — holds out such promise of providing super-strong materials or desalinating water inexpensively.

But there are enough safety questions to justify more yellow lights than either industry or government has yet deployed. The problem is that much too little is known about the risks posed by nanoparticles. The focus should be on getting industry and government to speed up research on their effects, from their production all the way to their disposal as waste.

On Monday, the UN Environment Programme called for “swift action” by policy-makers to evaluate nanotechnology and regulate it if necessary. Action throughout the industrialised world would help ensure that no single country’s firms suffer because of its regulators’ oversight.

The Environmental Protection Agency has been considering which course to take on nanotechnology. The agency could find guidance on its own website. A listing goes: “The size of nanoparticles is directly linked to their potential for causing health problems,” with very fine particles more likely to penetrate lung tissue. Both the United States government and industry should heed the United Nations’ urging and increase investment in the potential downside of super-down sizing.