Tuesday, October 01, 2013

Metro-NY AIHA Meeting on Vermiculite, Part 1

We attended the Metro New York (Metro-NY) American Industrial Hygiene Association (AIHA) chapter meeting on September 9, 2013.  This meeting was on the "New York State Asbestos & Vermiculite Analysis Guidance Update" it was presented in two parts, part one by Robert J. DeMalo, Senior Vice President of Lab. Services & Business Development and part two by Edward Cahill, Vice President of Asbesto, both from EMSL Analytical, Inc.  For pictures from the event visit Metro NY AIHA web album and for copies of EMSL's powerpoint presentation visit Metro-NY AIHA Meetings website for the Part 1 Handout and the Part 2 Handout.
Sample Passed Around the During the Meeting
Some very interesting facts from the first part of the presentation included:
  • The Libby mine was the source of an estimated 70-90% of all vermiculite sold in the US from 1919 to 1990.
  • Veins of asbestos contaminated most, if not all of the material taken from the mine; Libby Amphibole was an accessory mineral."
  • The Libby mine in 1926 opened up a vein of asbestos that is considered one of the largest deposits of asbestos ever uncovered.
  • Regardless of the method used to analyze the material a mixture of regulated asbestos as well as non-regulated asbestos is likely to be encountered.
  • "Libby Amphiboles" is a collective term for the complex mixture of amphiboles that are known to exist at the Libby mine site.  That mixture is Winchite (nonregulated amphibole); Richterite (nonregulated amphibole); and Tremolite (regulated amphibole).
  • Increased mortality rates are observed not only among the miners and their families, even in citizens with no direct connection to the mine.  Mortality rates are 40 times higher than the rest of Montana and 60 times higher than the rest of the US.
Based on the above information it is clear that Libby Amphiboles are the problem and that the nonregulated amphibole portions of the vermiculite is also a problem.  According to the US Geological Survey, the amount of asbestiform amphiboles contaminating the Libby vermiculite as approximately 84% winchite, 11% richterite, and 6% tremolite (American Mineralogist; November 2003; v. 88; no. 11-12; p. 1955-1969).  The mortality rate indicates a need to regulate these amphiboles plus others minerals that we now typically call elongated mineral particles (see NIOSH website for more information regarding asbestos fibers and other elongated mineral particles).  In our next blog post we will discuss part two of the vermiculite meeting.
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