woelen
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MSDS inconsistencies
I have the impression that there are many errors in MSDS documents and that these errors are parroted by sites like Wikipedia. As an example take the
MSDS documents for dichromates (K2Cr2O7, Na2Cr2O7, (NH4)2Cr2O7).
http://www.sciencelab.com/msds.php?msdsId=9927404
http://www.sciencelab.com/msds.php?msdsId=9927266
http://www.sciencelab.com/msds.php?msdsId=9927073
The potassium salt has indications 4,0,0,ox (you also find 4,0,1,ox)
The sodium salt has indications 3,0,0,ox
The ammonium salt has indications 2,1,1,ox
I would expect all of them to have the same indicator for toxicity. The ammonium salt is as toxic as the potassium salt, isn't it? I think that
indicator 4 is too high, but indicator 2 is too low. I would expect something like
3,0,1,ox for the potassium salt
3,0,1,ox for the sodium salt
3,1,2,ox for the ammonium salt (the ammonium salt is more reactive and can ignite, hence the higher values for flammability and reactivity).
I see this type of inconsistencies quite often, e.g. the sodium salt has only moderate toxicity, while the potassium salt is very toxic. I have the
impression that these when a certain salt is not common, then default values are assigned.
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alexleyenda
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XD You are right, that is strange... Well potassiums ions are really more dangerous than sodium ions if injected directly in the blood stream but if
they base their evaluations of dangerosity on "what does it do injected in the blood stream", what the heck x)
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gdflp
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I notice things like this often, though I don't find sciencelab MSDS's particularly good in general. Here's an example with tert-butanol where the
MSDS doesn't agree with itself!
http://www.sciencelab.com/msds.php?msdsId=9923195
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Pyrovus
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Quote: Originally posted by alexleyenda  | | XD You are right, that is strange... Well potassiums ions are really more dangerous than sodium ions if injected directly in the blood stream but if
they base their evaluations of dangerosity on "what does it do injected in the blood stream", what the heck x) |
If you were injecting dichromate into the bloodstream, I doubt you'd be worrying about the potassium that comes with it.
Never accept that which can be changed.
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Molecular Manipulations
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| Quote: Originally posted by Pyrovus |
If you were injecting dichromate into the bloodstream, I doubt you'd be worrying about the potassium that comes with it. |
Unless you know a thing or two about the extreme toxicity of potassium ions n the bloodstream. A lethal dose of potassium will kill
you ~100 times faster than the dichromate. Potassium chloride solutions are used as the main toxin in Capital Punishment executions. The lethal dose
is rather high (8 grams/80 Kg body weight), so an IV bag is likely a must, the pain is one of the worst imaginable, hence the use of pain killer in
legal executions, it causes a heart attack which is the main cause of death.
-The manipulator
We are all here on earth to help others; what on earth the others are here for I don't know. -W. H. Auden
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alexleyenda
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Yup, the thing is, something not dangerous at all on the skin, when integrated in the blood stream can cause incredible damages, because our body
relies on a very tight chemical equilibrium and the wrong chemical compound at the wrong place can rapidly fuck up everything. Some of these compounds
are obviously the poisons we know, but there are also other chemicals that seems harmless, because usually, when eaten, they are unable to go through
our filter membranes into the bloodstream, but if you shoot it right in your blood, you're gonna have a bad surprise. And well, that is the case of
potassium as Molecular Manipulation explained !
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Blunotte
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| Quote: Originally posted by woelen | | I have the impression that there are many errors in MSDS documents and that these errors are parroted by sites like Wikipedia...
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Yeah, I think the same.
Let us look, for example methanol.
Europe has the skull symbol, equivalent to 3 (Extreme Danger) format MSDS, like chlorine.
Further, in Europe has also Carcinogenicity symbol.
Instead MSDS reports 1 (Slightly Hazardous), like acetone 
EU simbols :  + 
Why?
In my opinion, those who have decided that symbols put, the night before he made full of ethanol 
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Blunotte
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In the European symbols, the bichromates have all the symbol of the skull and cancer, just as methanol ( ).
However, for methanol I think I know why.
Here in Europe, some years ago, crooks have used methanol for adulterating wine 
Here governments earn much with taxes on wine, and then the politicians are trying to prevent the purchase of methanol.
But this does not feel right: the hazard symbols should be independent from politics!
Here in Europe (expecially in Italy), the politicians are the worst scum that we can find, because they think only with their wallet 
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Cou
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Methanol is indirectly carcinogenic... the liver oxidizes it to formaldehyde.
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Blunotte
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Ok, but it's dangerous like the bichromates?
You can drink 5ml of methanol, and have no consequences.
Try to eat 5gm of bichromates, and then tell me how you feel 
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Deathunter88
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| Quote: Originally posted by Blunotte | Ok, but it's dangerous like the bichromates?
You can drink 5ml of methanol, and have no consequences.
Try to eat 5gm of bichromates, and then tell me how you feel
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Not sure you will have no consequences drinking 5ml of methanol. You will likely suffer vision impairment.
Quote wikipedia: "Methanol has a high toxicity in humans. If as little as 10 mL of pure methanol is ingested, for example, it can break down into
formic acid, which can cause permanent blindness by destruction of the optic nerve, and 30 mL is potentially fatal."
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Blunotte
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Here in Europe the limit for methanol in wine, is 0.25%.
Many farmers prepare wine, for their own use, with methanol above the limit allowed.
I know some of them who drink sometimes more than a liter of wine a day (fortunately not all and not always), and in this case they can take much more
than 2.5ml of methanol per day (sometimes, non alwaiys).ù
None of them, until now, has had problems with his sight.
The danger exists, it is true, but I think it is overestimated.
By much.
It does not justify an indication so severe.
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unionised
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The toxicity of methanol is greatly reduced if there's ethanol present as well; that's not a lot to do with the topic.
Also off- topic is the fact that as far as I can tell, all politicians think with their wallets.
Part of the reason why the Msds don't agree with each other is that they are fundamentally based on poisoning rats (or whatever).
Sometimes the rats are just a bit fitter and stronger than others- (or maybe are not observed for so long) so they survive.
Also, those pictograms are not European.
They are global, it's just that (like the metric system) the US may not have noticed them yet.
"The Globally Harmonized System of Classification and Labeling of Chemicals (GHS) is an internationally agreed-upon system, created by the United
Nations."
from
http://en.wikipedia.org/wiki/Globally_Harmonized_System_of_C...
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Etaoin Shrdlu
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I thought those pictograms were part of a European system first and the GHS incorporated them.
MSDSs are bad because there are authoring companies out there that just pull information from public databases and don't correct incorrect/missing
information. Case in point, I know one of them listed ethyl acetate as a solid simply because they had no volatiles data on it.
In addition there's no penalty for going overboard on the warnings. Telling someone methanol is drinkable, bad. Telling someone water's a deadly
carcinogenic hazard, sure, okay.
And yes, it gets parroted everywhere.
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Blunotte
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Nitric acid msds :
Reactivity zero?
It's right?
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Metacelsus
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| Quote: Originally posted by Blunotte | Here in Europe the limit for methanol in wine, is 0.25%.
Many farmers prepare wine, for their own use, with methanol above the limit allowed.
I know some of them who drink sometimes more than a liter of wine a day (fortunately not all and not always), and in this case they can take much more
than 2.5ml of methanol per day (sometimes, not always).
None of them, until now, has had problems with his sight.
The danger exists, it is true, but I think it is overestimated.
By much.
It does not justify an indication so severe. |
Drinking methanol with large amounts of ethanol is different from drinking it by itself. The enzymes that turn methanol into formate are the same ones
that turn ethanol into acetate. Thus, having lots of ethanol present reduces methanol toxicity by slowing down conversion to formate.
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woelen
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@Blunotte: I found another MSDS on HNO3, which has 4,0,0,- (no mention of its oxidizing properties). I would give it something like 3,0,3,ox. Very
weird. The MSDS's for HNO3 strongly underestimate its reactivity.
The same source gives 3,0,3,ox for 60% HClO4. I would give that 3,0,2,ox, but 3,0,3,ox is OK to me as well.
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