Following the widely publicised release of Song et. al.'s study into lung disease in Chinese workers expoed to nanoparticles in the workplace (accessible here), there was of course much discussion within both the nano and wider community as to the paper's implications and its issues. SAFENANO published a special feature on the paper, outlining the paper's main findings and issues, and in association with Andrew Maynard of the Woodrow Wilson International Center for Scholars, three fascinating blogs discssing various aspects of the paper and providing opinion from some of the world's most respected nanotechnologists on the matter were published. SAFENANO's attempts to help the wider science community form their own informed opinion on the paper's findings were well covered by the 'nano-specific' press, and as ever we hope that the materials we provided served a useful purpose! In amongst all of this this, i had some interesting correspondance with Alastair Robertson, an expert in occupational exposure to chemicals and dusts and previous Director of Consultancy Services for IOM. My original feature on the paper raised a question mark around the chemical 'ethylene dioxide', an ingredient reported to be in the coating paste preparation used by those workers who fell ill, and for which i struggled to find further information. Alastair provided me with the following additional information on this chemical, and some insightful comments on those chemicals used within the paste as a whole, which he has kindly allowed me to publish:
Ethylene dioxide is occasionally used in error to describe ethylene oxide but it also occasionally used as a synonym for 1,4 dioxane, a carcinogenic solvent. Diethylene oxide is more commonly used as a synonym. The link below gives useful toxicological information on 1,4 dioxane:
http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s080diox.pdf
The description of the process seems poor and it is difficult to be definitive. 1,4 dioxane but it is commonly found as a contaminant and is used in some paints. I would not expect much ethylene oxide from what was said about the paint although it could be present in trace amounts from the production process. Interestingly, some paints in the US are described as possibly containing traces of both ethylene oxide and dioxane. On a wider note, I also suspect that there would be very little chemical decomposition or smoke at the temperatures quoted (75 -100 C) but solvents, plasticizer, any monomers and other low boiling point additives may be volatilised. Chemical decomposition of the product is generally undesirable in a painting process as it wrecks both plastic and the finish. Smoke would cause stains.
Thanks to Alastair for providing this information.