This week, BSI (the national standards body of the U.K.) published what is perhaps the most practical guide to working safely with engineered nanomaterials to date.
“Nanotechnologies – Part 2: Guide to safe handling and disposal of manufactured nanomaterials” (aka PD 6699-2:2007) is one of BSI’s “
nano-nine”: nine nanotechnology documents either published or under development “designed to show how standardization can be used to help ensure [nanotechnology’s] successful global development and growth”. It’s downloadable for free from
here.
Is the document any good? Here’s the short answer:
If you are developing, producing, handling, or otherwise working with engineered nanomaterials,
READ THIS GUIDE!
Now for the long answer, and something of an indulgent pre-amble:
In late 2004, I helped draft a set of 64 Frequently Asked Questions on Nanotechnology, Occupational Health and Safety (the nano-FAQ) while working at the National Institute for Occupational Safety and Health (NIOSH). The questions (and answers) were pretty blunt, and aimed at getting the best available knowledge at the time into the hands of workers, and people who would make decisions on workplace health and safety. And so we included questions like:
- “Is there any way of estimating appropriate exposure limits for nanomaterials, based on current exposure limits?"
- "Are there specific regulatory requirements or guidance for the disposal of nanomaterials in research and manufacturing settings?"
- "Do carbon nanotubes behave like asbestos?"
This document was never published—amongst many more legitimate reasons, using the word “risk” was considered too inflammatory at the time in a nanotech workplace health and safety document.
Much of the information in the nano-FAQ was eventually repackaged and published as
“Approaches to Safe Nanotechnology An Information Exchange with NIOSH” in late 2005 (and I’m glad to report that the word “risk” appears 61 times in the 2006 update of the document) – a tremendously useful, if rather cautious, discussion on nanotechnology in the workplace.
Three years after the aborted nano-FAQ, the BSI guide reminds me very much of what we were trying to achieve then: to provide the best possible advice in the most accessible form on working as safely as possible with engineered nanomaterials. And to the credit of the authors, the guide does a far better job that those early frequently asked questions did in highlighting what is important, and helping make the best possible decisions that current knowledge will allow.
The BSI guide will surely attract its fair share of criticism – honest advice often does. But I wonder how much of that criticism will come from people motivated by profit, rather than protecting people’s health. If, on the other hand, you want to ensure that your nano-workforce are protected to the best of your ability, the help and advice laid out in PD 6699-2:2007 is a good starting point.
Like a number of previous documents, the guide takes a cautionary approach. For instance, the “
Standard Guide for Handling Unbound Engineered Nanoscale Particles in Occupational Settings” recently published by ASTM International suggests that:
“Until clearer understandings emerge, the limited evidence available suggests caution when potential exposures to unbound engineered nanoscale particles (UNP) may occur.”
While the U.S. Department of Energy document
“Nanoscale Science Research Centers Approach to Nanomaterial ES&H” states:
“Laboratory personnel should treat ‘all new compounds, or those of unknown toxicity, as though they could be acutely toxic in the short run and chronically toxic in the long run’.”
In effect, the BSI document assumes nanoscale versions of materials are potentially more harmful than non-nanoscale versions
unless they are shown to be otherwise.
The guidance presented is firmly grounded in good occupational hygiene practices, and draws heavily from previously published documents. And so the sections on “general approaches to managing risks from nanoparticles,” and the “hierarachy of controls” should come as no surprise to occupational hygienists and those who have been following the field.
In tackling risk evaluation, the guide proposes four categories of material:
- Fibrous: a high aspect ratio insoluble nanomaterial;
- CMAR: any nanomaterial which is already classified in its larger particle form as carcinogenetic, mutagenic, asthmagenic or a reproductive toxin;
- Insoluble: insoluble or poorly soluble nanomaterials not in the fibrous or CMAR category;
- Soluble: nanomaterials not in fibrous or CMAR category.
This pragmatic classification makes a lot of sense based on current understanding, and lays the basis for proposing rules of thumb for estimating Workplace Exposure Limits (WELs) in the absence of more detailed information.
This is perhaps going to be one of the more contentious aspects of the guide: clear guidelines on how to set your own exposure limits if no-one else is coming up with anything better! I hear the murmurings of the mob now: “how could they be so naïve: suggesting exposure limits when we don’t have hard data—don’t they realize the legal and commercial ramifications?!”.
But what about the workers? Let’s face it, if you are working with engineered nanomaterials now, your WEL options are limited: use existing non-nano exposure limits, do nothing, or act as if every nanoparticle is a potential killer. None of these makes sense from a health or a business perspective.
What the BSI guide does is provide a pragmatic solution – a way for businesses to set their own limits in the absence of any better information. And I have to say, the recommendations make sense to me. In brief we have (again, in the absence of any better information):
- Fibrous nanomaterials: 0.01 fibres/ml;
- CMAR nanomaterials: 0.1 x the existing material WEL;
- Insoluble nanomaterials: 0.066 x the existing material WEL [based on draft recommendations from NIOSH for nano-TiO2]; and
- Soluble nanomaterials: 0.5 x the existing WEL.
While you could legitimately argue over the precise values and multipliers proposed, the overall result is to provide goals to work towards that can only help reduce the chances of adverse consequences.
The other section of the guide I suspect will raise a few eyebrows is the one addressing disposal procedures – I can hear the cries of “Over-cautious! Over cautious!” ringing in my ears as I type! Yet how do you get rid of those spills, off-spec production runs, experimental samples, and nanoscale waste products?
One document that has risen to the challenge (apart from the BSI guide) is the U.S. Department of Energy’s “Nanoscale Science Research Centers Approach to Nanomaterial ES&H.” This is a solid document in itself, and so perhaps not surprisingly, the BSI guide draws heavily from it—in places duplicating the DOE document verbatim.
The result is eminently practical advice on how to get rid of unwanted nanomaterials—as always, in the absence of any better information.
To wrap up, the BSI guide is not perfect—for instance, nanoparticles formed in liquids don’t appear to get a mention, and I am not 100 percent convinced by the suggestion for a particle number-based exposure level. But overall, this is the most direct, concise and helpful document of its kind I have read.
That is not to say that it supplants other nanotech workplace health and safety guides. On the contrary, the BSI document complements what is already out there (and what is to come, looking to the anticipated ISO technical report addressing workplace health and safety). Documents from HSE, NIOSH, DOE, ED and DuPont, ASTM and ISO together provide a valuable resource for anyone developing strategies for ensuring nanotechnology-related workplace risks are as low as reasonably practicable—each brings something unique and valuable to the table.
In the case of the BSI guide, its value lies in down-to-earth know-how. This is a shop-floor manual for making decisions where the rubber hits the road.
So if you are working in any capacity with engineered nanomaterials and want to be as safe as you can be, download the guide and read it. It might just change the way you do things.
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Disclaimer:
I should add that BSI document PD 6699-2:2007 was developed with extensive input from the SAFENANO team. However I was not part of this process, and did not see the document until its final version. As a result, the flaws, biases and unbelievably large knowledge-gaps reflected in my comments are mine alone, and do not reflect those of the SAFENANO team