The ACGIH® Board of Directors ratified the 2012 Threshold Limit Values (TLVs®) for Chemical Substances and Physical Agents and Biological Exposure Indices (BEIs®) on December 9 and 15, 2011. The Board also approved recommendations for additions to the Notice of Intended Changes (NIC). For a listing of the substances that were acted upon, click here. The complete Annual Reports are online at the ACGIH® Online Publications Store. Cost to purchase this reference book is $50
This is good work and information by ACGIH, but it still only covers OELs for several hundred chemicals.
OELs have been established for over 6,000 DIFFERENT CHEMICALS by regulatory agencies in over 50 countries. These OELS can be found in "Global Occupational Exposure Limits for over 6,000 Specific Chemicals." http://www.oehcs.com/global_exposure_standards.htm. Cost to purchase the book is $140.
These OELs have been established by the toxicological experts in those countries.
The Army, Navy, NIOSH, DOE, numerous chemical companies all use this book for chemicals for which ACGIH has not established any OELs.
If you use a chemical with no TLV, you need to consult this reference.
Categories: Ed Stuber
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Over the past ten years, the amount of material that may collect on the side walls of a cassette has become more broadly recognized as a significant contributor to the total amount of material collected during sampling. Both NIOSH and OSHA have issued guidelines stating that these deposits should be included with the analysis prep whenever possible. Galson has followed these guidelines, for example we wipe out the inner walls of the cassette and add the wipe to the digestion tube for metals analysis.
However, we cannot do this with filters collected for gravimetric analysis. The filters must be handled delicately and while loose material may be placed on the filter prior to weighing, there is no way to add the wall deposits. Recently the problems this might cause were highlighted when a client collected calcium carbonate samples using a matched weight MCE filter. The calcium carbonate results were up to 60% higher than the gravimetric results due to the high amount of material deposited on the side walls of the cassette. The problem was aggravated by the pure and electrostatic nature of the material sampled, but can be a problem whenever gravimetric analysis is followed by another technique that allows for side-wall material to be included.
We plan on footnoting analyses where this problem is observed and are also investigating alternative solutions. IOM samplers for example are weighed as a unit, which means that deposits on the side wall are included in the gravimetric results. The filter in the IOM head can be varied according to the subsequent analysis desired, which makes this a potential solution, although only the inhalable fraction of the sample will be collected. There is also a product called ACCU-CAP which also is weighed as a unit, but we have to do some studies to see if this type of filters is acceptable for further analyses.
The limitations of NIOSH 0500 and 0600 are becoming more and more in focus. Galson recognizes the problem, is taking action, and wants you also to be aware. Here is a link to some NIOSH guidance on the subject: http://www.cdc.gov/niosh/docs/2003-154/cassetteguidance.html
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The old “Hi I am from the government and I am here to help you.” saying is trying to strike again. This time government is trying to alter the rulemaking process within OSHA. As if OSHA doesn’t already have a tough row to hoe in getting new regulatory rulemaking in place. Currently, OSHA has been trying to get 3 compounds of interest - beryllium, diacetyl, and silica dust - updated with new regulatory limits. It has been 9 years since OSHA started the process with beryllium, 4 years with diacetyl, and 8 years with silica dust. So let’s pile on some more government rules to slow them down even more. Does that sound like a good idea? How many excess cases of cancer and other disease must we endure before we come to our senses?
Two bills seeking to “reduce the burden on employers by regulatory agencies” (i.e. OSHA), have passed the House and are awaiting action in the Senate. One bill would have OSHA pursue alternatives and present additional evidence for the necessity of the proposed regulations. The other bill would require agencies to conduct a cost-benefit analysis of regulatory alternatives, and then adopt the least-costly alternative.
Proponents of the bills say regulations have become a barrier to economic growth and job creation with opponents argue that regulations improve productivity and save businesses money in the long run.
Which side do you fall on? As a health and safety professional – I know where I stand.
Categories: CIH
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In the January edition of the Journal of Occupational and Environmental Hygiene (pps 1-13), there is an interesting study of the potential for nanoparticle release during the shredding of plastics reinforces with nano materials. The study is interesting not only in its conclusions, but in the differences in measurement between the various instruments and procedures used to assess the exposure.
Nano materials are added to plastic car parts in order to maintain or improve thermal stability and stiffness while reducing weight. Since up to 84% of cars are recycled, including the plastic components, it was theorized that as cars containing these new materials were shredded during the recycling process the workers involved could be exposed to released nano materials. Since nanoparticles have been shown to have a stronger impact on respiratory disease than an equivalent mass of a larger particle size, the potential exists for a hazardous exposure during this type of operation.
The research team assessed the potential for exposure by shredding specially made components. Some of the components contained one of two commonly used nanomaterials while others contained only the polymer material. The dust produced during shredding was collected and analyzed. Surprisingly, more nano-sized particles were produced when the plain materials were shredded than when the composites containing the materials were processed and no nano materials were observed in the shredder dust via electron microscopy. No mechanism for these finding were suggested, but it probably relates to the bonding strength of the nano material with the plastic when the composite is formed.
Not only are these results interesting, but so are the instruments the team used to measure the particles, and the way the function of each instrument produced a set of data, that if interpreted on its own would cause a different overall set of conclusions. The data had to be interpreted from a macro standpoint taking into account the biases caused by the measurement mechanism of each instrument in order to come up with a cohesive conclusion.
Several of the instruments used, the P-Trak, Dust Trak, and gravimetric filters with a PM 2.5 inlet did not measure particle concentrations during shredding that were different from background. A “Fast Mobility Particle Sizer” (FMPS) Spectrometer however measured particle concentrations substantially higher during the shredding of all three types of material. This is because of the small mean particle size produced. In all three tests the vast majority of particles were less than 20nm in diameter. Instruments like the P-Trak are less sensitive to particles in this size range and thus underestimated the concentrations during shredding. The research team expected larger sized nano particles to be produced because of the dimensional sizes of the two materials used in the composite. The fact that the particle size generated was smaller than expected and that the concentration was higher shredding the non-composite materials indicates that the nanoparticles are being produced by a different mechanism than the simple release of the nanomaterials used in the composites. It also illustrates that the ability to measure particle size over a wide range is essential in order to observe the entire picture of what occurs during the operation being measured. At least to me, this study indicates that the FMPS might have significant advantages and might be the instrument of choice in measuring nanoparticle generation.
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