November saw the publication of a commentary in Nature Nanotech bearing the title “The US must help set international standards for nanotechnology” (here). As the title suggests, the document was an exhortation for the US to take an active role in the development of standards, particularly through the International Standards Organisation (ISO) programme. Further, the commentary states that representatives from all nations must ensure that all standards are based on sound science. While, that all sounds very laudable, it is perhaps surprising that Nature nanotech deem it worthy of a two page commentary, particularly given that the US are already highly active in the area of standardisation. For example ISO229, Nanotechnologies, in which I participate, out of 39 member countries, the US always has one of the largest delegations. The US also chairs Working Group 3, Environment, Health and Safety.
The commentary goes on to discuss two standards, one of which has just been published by ISO, and the other which has just been adopted as a new work item. This new work item is based on the British Published Document (PD) BSI 6699-2 (title, link). The authors are highly critical of this document, stating “If BSI is successful in converting this PD 6699-2 into an ISO standard, such an international standard could lead to controls and restrictions on the manufacturing and use of nanomaterials, similar to the way that asbestos risk control standards of the twentieth century culminated in import and use restrictions.” As the leader of the team who will develop this standard under ISO, I am a bit surprised at what appears to be an attempt to influence development of this standard from out-with the ISO process, and in what seems to be misrepresentation of the purpose and intent of this standard.
There are two issues central to this critique. One is that the BSI document is not based on sound science, that it is premature and that it will be misinterpreted by the user. The second is that this document will be somehow forced through the ISO process by BSI.
I led the team which wrote the BSI document and so I feel duty bound to try to add some clarity to this argument. PD 6699-2 was developed to provide timely, pertinent and pragmatic advice to industry, and other relevant organisations, on current thinking regarding the precautions that should, in the absence of clear regulations relevant to health and environmental toxicology of nanoparticles, be adopted when handling and disposing of engineered nanoparticles. As with all other standards documents, it is subject to regular review and updating to take account of the current state of the art.
In its “scope” PD 6699-2 “recognizes that there is considerable uncertainty about many aspects of effective risk assessment of nanomaterials, including the hazardous potential of many types of nanoparticles and the levels below which individuals might be exposed with minimal likelihood of adverse health effects. The guide therefore recommends a cautious strategy for handling and disposing of nanomaterials entirely consistent with that promoted by almost all international organisations, including for example the UK’s Health and Safety Executive (HSE). However, at the current time, no occupational exposure limits specific to nanomaterials have been published and it is hard to see this changing in the near future.
Most regulatory guidance to date has been of the form “if you think nanoparticles are hazardous you should minimise exposure”. While this is clearly sensible, it is hugely difficult for the recipients of this guidance to interpret given the current knowledge gaps.
Where 6699-2 has gone further than the regulators have gone thus far is in an attempt to frame the guidance in terms of what it calls “benchmark exposure levels”. These are not intended to be occupational exposure limits. These are intended to help users understand and interpret measurements made to demonstrate effective control of exposure in their workplaces. As is acknowledged (and highlighted in bold) in the text, “Although these benchmark levels relate to current exposure limits, they have not been rigorously developed. Rather, they are intended as pragmatic guidance levels only”. 6699-2 is clear that there is (probably) insufficient evidence available on which formal limits could be based at this time, and even if it was available for one material type, implementing these internationally will be the subject of intense debate (as has been sees with the attempts of NIOSH to implement a new limit for ultrafine (nano) TiO2 ).
The key issue is though, what should people using these materials do right NOW. In writing the BSI document, we considered that the benchmark levels were the most appropriate way of filling the gap in the short term. Other approaches, including for example, giving guidance to users as to how to set their own “in-house” limits, are also possible.
The authors of the Nature Nanotech commentary counterpoint the pragmatic approach in BS6699-2 using the example of asbestos regulations, which they state were based on “exhaustive risk assessment analyses and “evidence of significant risk”. (Actually, this is not my view of how the asbestos regulations developed which I would generalise as becoming increasingly restrictive as the evidence became available) However, it is nothing short of extraordinary to consider the development of the asbestos standards as some kind of exemplar for regulatory process. In the UK alone there are estimated to be 4000 people per year dying from mesothelioma as a result of a failure to control exposure to asbestos to a safe level. The latency period of this disease means that the numbers are still rising and will continue to do so for several years. Clearly many lives might have been saved if the control of asbestos had been based on “pragmatic guidance levels” rather than waiting for “exhaustive risk assessment analyses and “evidence of significant risk “
The thinking in the Nature Nanotech commentary seems to be that it is much better not to give practical, pragmatic guidance in case it is taken out of context. I disagree. My experience is that users of nanoparticles are desperate for such practical guidance which they can apply to make their workplaces safer and healthier for their workforce.
Dealing secondly with the matter of the standardisation process, the document will not be “converted by BSI”, it will be developed by due process firstly within an ISO working group, comprised of experts from all of the member countries who choose to nominate a representative and then at full committee stage, in which in which international consensus will be reached. The first meeting of that working group was in Shanghai last week. There was good agreement about the scope and aims of the document and good discussion about the various options as to how this might be met. I’m confident that we will be able to develop this document to a point where consensus can be achieved.
In the meantime, if you can’t wait for the ISO document, you can still download BS6699-2 free from the BSI site here.
You can read Andrew Maynard comments on BS6699-2 here.
Rob Aitken