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From: Monona Rossol All, I just read with much interest the article in the Journal of Chemical H&S "Toward a comprehensive framework for nanomaterials: An interdisciplinary assessment of the current Environmental Health and Safety Regulation regarding the handling of carbon nanotubes."
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Sent: Sat, Sep 7, 2013 10:05 am
Subject: JCH&S July/Aug 2013 nano article
It is mostly a great article, but as you can probably guess, I found stuff to kvetch about.
Here's the thing: The closest the authors got to the issue of air quality limits was the outdated OSHA graphite PEL of 5 mg/m3. Clearly, no one with any conscience would use that limit, not even in the most avaricious nano industries. Plus, under the General Duty Clause, OSHA can theoretically cite using better standards. The ACGIH limit of 2 mg/m3 for graphite at least should have been mentioned. And there is an even lower German Fed Research Standard that has been adopted by some countries.
But assuming that the article wants to stick to US regulations and standards, they talked about OSHA and NIOSH, noting that NIOSH standards are not "federally mandated." The footnote for NIOSH references a call for public comments on a proposed bulletin on exposure to carbon nanotubes. Naughty, naughty, guys. That bulletin (# 65) was published in April of 2013. Plus, NIOSH has other bulletins on nano topics that should have been included--more later.
Most importantly, the OSHA and NIOSH information did not include the fact that in 2011 NIOSH set the first ever occupational air quality standard for a nanoparticle. I could be wrong, but I think this is a first anywhere in the world. That's news.
This new recommended exposure limit (REL) is for nano TiO2. This nanoparticle has been around for decades since it is a white pigment and the paint industry learned early that the smaller the particle, the less they would need to get the same coverage in a paint. So there is more study of these nanoparticles than any other. Just FYI, look at the various time weighted average (TWA) limits:
OSHA PEL 15 mg/m3 total dust (all sizes)
ACGIH TLV 10 mg/m3 with a notice of intended change to lower that to 1 mg/m3 for respirable
NIOSH REL 2.4 mg/m3 for respirable
NIOSH REL 0.3 mg/m3 for nanoparticles
There is another reason not to ignore this TiO2 issue in this article, and that is that the authors cover the preliminary cancer evaluations for carbon nanotubes and fibers in detail. Now if they only want to talk about CNT and CNF, this is OK, but the article's title says it is about nanoparticles. The TiO2 story is relevant because NIOSH was the only agency to list TiO2 as a carcinogen. They listed is decades ago, stuck to it, and no one agreed--until 2010 when IARC reevaluated the existing data in terms of particle size. IARC now lists TiO2 as 2B.
Even more relevant to the article would be some mention of NIOSH Bulletin 63 on TiO2. I think it would have been enlightening to quote even one sentence from their conclusion in this document that:
"...TiO2 is not a direct-acting carcinogen, but acts through a secondary genotoxicity mechanism that is not specific to TiO2, but is primarily related to particle size and surface area."
Whoopie damn dooo, class! So NIOSH has reason to believe that lotsa itsy bitsy stuff can cause cancer. And this revolting development was generated primarily by our wee NIOSH with only a morale boost from IARC.
And we're not done here, because the NIOSH Bulletin 65 mentioned above on occupational exposure to CNT/CNF published in April 2013 sets more limits. It says: ...NIOSH now recommends an exposure limit at the current analytical limit of quantification of 1 ug/m3. Oops. How low is that again? Micro what?
I also like this story because it is a relief to me in lectures to be able to point to at least one thing the US has done recently in occupational health that is both right and first. And if you look at both the current information and history of limits, you would note that NIOSH is usually first-est with the most-est. That's what happens when you isolate a bunch of underfunded smart people and give them no power to do anything but think about stuff.
Monona Rossol, M.S., M.F.A., Industrial Hygienist
President: Arts, Crafts & Theater Safety, Inc.
Safety Officer: Local USA829, IATSE
181 Thompson St., #23
New York, NY 10012 212-777-0062
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