Joseph Alkana wrote: > Thanks for sharing this info with us. I do wonder if something is missing > from that chart on exposure to those chemicals. For instance the list gives > the volumes in ratio form but where are the absolute exposure times? Could > you supply that data? Also do you know if any of the mentioned chemicals > have any build up effects in the system over time as opposed to an absolute > exposure for so and so time? > > Thanks > > Joseph Alkana RPT Joseph and anyone else interested: I'm afraid that's all the info I have in my bookcase. Any university library ought to be able to help. The reference librarians are usually happy to find that kind of thing for you. The more complex organics, especially aromatics, which are based on a benzene ring with various additions and substitutions (toluene, xylene etc) are known carcinogens. Any with chlorine substituents should be viewed with even more caution. These molecules, being fat soluble, are more likely to be retained in the body for extended lengths of time, and hence have a greater capacity to do damage. The smaller alcohols and ketones methanol, ethanol, propanol, acetone, are more soluble in water (as well as in fat) so they are more easily eliminated. Unfortunately, there is not a strong relationship between acute toxicity and long-term exposure effects. Everybody knows that you can drink agent orange and it won't kill you. You can bathe in 2,4-D. But come and see me in 20 years. Almost any chemical sold nowadays in Canada has available WHMIS information sheets (Workplace Hazardous Materials Information System) and any commercial or institutional user is required to keep this information on file and make workers aware of it. I don't know about the US. These sheets outline all known hazards and appropriate precautions. I would treat them as minimum precautions. The thing that I like to point out (referring to the partial list I posted just as an example) is this: Just because it is permissible to be exposed to all of those things at the levels described, does that mean that it is also permissible to be established to a cocktail of all of them in those proportions at a total concentration of 3800 ppm? You could keep adding different compounds at their permissible concentrations until there was no actual air in the mixture. Regards, Tim Keenan Noteworthy Piano Service Terrace, BC.
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