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MistaMiyagi
Dream Team
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Joined: 06 Feb 2005 |
Posts: 50 |
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19.22 Points
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General Chemical Safety
Sun Feb 13, 2005 3:50 am |
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Above all, protect yourself!
Serious chemistry requires serious chemicals.
Serious chemicals can cause serious injuries.
Proper protective equipment includes more than just a pair of denim jeans and a ripped T-shirt. Always wear appropriate clothing, and remember that your body can repair but not regenerate.
- Close-fitting but comfortably sized shirts with long sleeves
- Pants, not shorts! NaOH burns prove that shorts are not a good idea!
- Goggles should always be worn when there is ANY chance of splashing.
- Latex gloves are the closest thing to useless. Use nitrile, at least.
- A fume hood or adequate ventilation should be used around volatiles.
- Acid burns can be neutralized by copious amounts of baking soda paste.
- Alkali burns can be neutralized by copious amounts of common vinegar.
- If breathing starts hurting, it's time to stop and get the hell outside. The respiratory tract (throat, windpipe, lungs) is one of the most sensitive systems of the body and one of the slowest to repair.
- Throw away the ipecac, bees - The best thing you can do if you accidentally ingest a small amount of poison is to drink lots of water or milk. If it's a large amount - or a small amount you start to feel ill from - call the medics, you're getting a charcoal cocktail.
- Know first aid and basic cardiopulmonary resuscitation (CPR)... especially if you are not dreaming alone. The medics, even when called, will take a few minutes to arrive. Those few minutes may mean the difference between your friend recovering with only a headache and your friend permanently thinking he is a carrot.
I will be adding to this intermittently, but feel free to throw something on here about general chem safety... anything that is specific to a situation will be split off into a new topic.
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IndoleAmine
Dreamreader Deluxe
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Joined: 09 Feb 2005 |
Posts: 681 |
Location: Bahamas |
18717.10 Points
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Wed Feb 16, 2005 9:23 am |
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Erhm - speaking technically, lye and acid burns can be neutralized to give a not dangerous salt and maybe carbon dioxide.
Would you really want an open flesh wound with lots of salt in it, bubbling from CO2 - instead of a simple acid burn? You don't want anything like that, I promise you.
The proper first-aid measure is WASHING! wasdhing with lots and lots of cold water is the one and only way to treat corrosive burns of any kind and avoid further damage. Of course together with
a) further, prolonged rinsing of the affected area(s) with lots of cold water
b) removing the affected clothing and
c) calling an emergency medician immediately.
At least that is what they say in every MSDS of corrosive acids and bases - and in the "laboratory safety" manual of my university too... 8)
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- If breathing starts hurting, it's time to stop and get the hell outside. The respiratory tract (throat, windpipe, lungs) is one of the most sensitive systems of the body and one of the slowest to repair.
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Then it may be too late already - if you stay in a room filled with HCl-gas until it starts to hurt, you can be sure you'll have severe lung burns afterwards (chemical pneumonitis, or simply worst chemfreak asthma...)
Better place some universal pH indicator paper strips around yourself, here and there in your lab: if corrosive gases of any type are in the air, you will see it by the red or blue coloration of these pH strips BEFORE it starts to hurt. And you can leave the lab before its too late - i.e. BEFORE your lungs corrode...
Greetz. I_A |
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MistaMiyagi
Dream Team
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Joined: 06 Feb 2005 |
Posts: 50 |
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19.22 Points
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Tnx indoleamine
Thu Feb 17, 2005 3:30 am |
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You make some valid points, but I disagree with a few parts.
Dilution and washing are the best overall methods to treat any type of contamination, which is a valid point you make.
However, you make mention of salt in a wound - a painful thought, true. The problem here is that if you are dealing with a concentrated reagent, dilution will slow the chemical burn but not stop it entirely. If the skin is still intact, washing poses no additional danger. However, once the skin is broken and the living dermis and subdermis / reticular layer is exposed, dilution poses several issues:
- Washing of dilute - but still reactive reagent - into the deeper layers of tissue.
- Creating a hypotonic enviroment which encourages the influx of water (and depending on the nature of the reagent, possibly the solute as well) into cells.
- Depending on the nature of the reagent (solid NaOH comes to mind), you may encourage an exothermic reaction, causing a thermal in addition to chemical burn.
Even salt in the wound - painful and creating a hypertonic environment - is better than leaving the reagent there. Cells will exude water and some may be damaged due to crenation, but any cell is more capable of dealing with a fluid imbalance than a permanent denaturation of its membrane. For example, a cell will live much longer in a hypertonic saline environment than with its lipid layer being saponified by a strong alkali.
By neutralizing the reagent you remove its effect altogether, which becomes significant in that some chemicals will not only destroy living tissue but impair or even prevent its future repair.
I think this all boils down to knowing the precise nature of your reagents. Dilute acids or dilute base contamination is indubitably handled better by dousing with water, but as the potency of your reagent increases, the priority becomes less of a "spread the damage with water" to "neutralize it where it is." And I would hate so see anyone attempt to stop, say, a lithium contamination by dilution... yikes.
The best, of course, would be a thorough shower with a buffered solution. However, not many chemfreaks have an emergency shower hanging in their kitchen/laboratory/basement/shed.
Like the idea about the litmus sensors though! |
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IndoleAmine
Dreamreader Deluxe
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Joined: 09 Feb 2005 |
Posts: 681 |
Location: Bahamas |
18717.10 Points
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Sun Feb 27, 2005 4:52 pm |
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With lithium, it is certainly another story, as well as with bromine, NaBH4 or LAH...
But with strong acids and bases, believe me the best remedy is plenty of cold water. Dilution is they key here, as you mentioned: even H2SO4 isn't harmful in 0.001N concentration, and the exothermic reaction you talk about is more likely to occur when you react concentrated acid with concentrated buffer solution, WITHOUT any cold water being present to take up the excess heat.
And since open wounds bleed, I bet there will be no corrosive substance entering your tissue if you suffer from a severe corrosive burn, at least if it bleeds.
(Not even at universities "buffer solution emergency showers" are available, they simply have plain water emergency showers - although so many students happen to have accidents again and again...)
I was specifically told NOT to treat acid and base burns with neutralizing agents, that's why I'm saying this.
i_a |
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