Sciencemadness Discussion Board - Common accidents in the lab and how to avoid them

Common accidents in the lab and how to avoid them

Picric-A - 17-9-2008 at 08:18

I found this video an i realised it would be a great topic to start about accidents in the lab:

http://video.google.co.uk/videoplay?docid=567670423497427135...

I am sure everyone has had accidents in the lab, however small

If you feel up to it, please share them here!

About a year ago (when i was young and stupid

) i bought a bottle of drain cleaner (conc sulphuric acid) I decided to store it as a 50% soloution so i added all the drain opener (1.5L) to a 5liter beaker. To the conc sulphuric i added around 1.3 liters of water :O The next thing i knew was the beaker was sprewing out steam, H2SO4 and goodness knows what

Remember AAA!

[Edited on 17-9-2008 by Picric-A]

12AX7 - 17-9-2008 at 09:33

Excellent clip. And hot chicks doing chemistry is really hot (even with the British accent).

Tim

Formatik - 17-9-2008 at 10:44

The most basic thing to do is have a look at the MSDS sheets and look at the incompatibles and hazards and that will help avoid the large majority of accidents. Then there are books like Bretherick's Reactive Chemical Hazards (here), that go more into detail. Taking the right precautions is also what will make sure that one of those accidents doesn't affect you.

Klute - 18-9-2008 at 11:24

Especially with a british accent!

Picric-A - 18-9-2008 at 12:25

haha, funny she has to go out for the exploding H2

then it doesnt work

panziandi - 18-9-2008 at 12:37

HaHa I had a similar problem with the bloody CuO/Mg thermite!

"and at number 8, yes its not banned it's white phosphorus"

[Edited on 18-9-2008 by panziandi]

Jor - 18-9-2008 at 14:24

A few nasty things.:

1.
In the preparation of potassiumperoxochromate, the liquids were not cold enough. When adding H2O2, the liquid began bubbling vigorously, spuwing aerosols of carcinogenic chromium in the air. Immediatly set erlenmeyer outside. next i took a botlle of K-metabilsulphite quikly, took a gram, added conc. HCl, and carefully inhaled the SO2, for a minute or so, at non-irritant concentration.

2.
preparing bromine. Lost the smell for it that day. So didn't realize exposure. Got some pain in my nose after.

3. Throwing some very fine copper powder in conc. nitric acid outside. it spuwed at once 300ml of pure NO2, in like 1 second, really surprised me. Didn't get hurt.

4. When disposing of a bisulphite solution, I didn't expect that cloud of SO2 coming out of solution when pouring it in the sink. Hit me hard in the nose, quite freshning. Lost my cold though

5. Creating about 5 grams of nickel carbonyl and venting it in a closed room. I breathed it all, but survived.

Stupid mistake, not dangerous:
Beaker was hot, and I wanted to cool it. At that moment I forgot it would ofcourse break when touching cold water. And it did. Worth 3 EUR.

I'm not doing home chemistry very long now, but I'm getting more and more experience quickly. These mistakes will not be made again. However, considering the things I sometimes use, I did not do to bad, as these were my only real accidents. There is no very dangerous situation. The most uncomfortable experiment I do is preparing bromine. Even when putting a fan (a blower, the ones you put ina bedroom for cooling) in front of the door with my working table between the fan (mine is very powerful) and door, you still smell it, and may become irritant (irritant is <10ppm). I try to do the synthesis very quickly, producing about 2mL's a run (I use very small amounts in micro-experiments, and making larger batches is too dangerous), in about 10 minutes. I guess average exposure 10 minutes is a few ppm, its non-irritating, but smells horrible.
between door and
Ofcourse, 5 is a joke

[Edited on 18-9-2008 by Jor]

[Edited on 18-9-2008 by Jor]

panziandi - 18-9-2008 at 15:29

Good job its a joke!

The human nose is VERY sensitive to the odour of the halogens, indeed bromine comes form bromos the Greek for stench!

I have had few accidents:

1) squirting alcohol onto CrO3 lighting it with a match then after extinguished squirting more onto the CrO3 only to find it ignite shoot back into the bottle and blow it out of my hand and deafen me for a bit (and my onlookers!), that was just after being told by my gramps "hope you aren't doing anything that will explode or disturb the neighbours" ... it was like a percussion grenade!

2) wrapped PVC tape around my PCl3 bottle only to have the lid break apart and the PCl3 spill... mainly on my bench but some on my hands and I was worried if it was on my face/clothes so I ran for a shower! Luckily I wasn't burnt but I could smell it all day!

3) adding MeOH SLOWLY to H2SO4 but forgetting that methanol boild a *little* lower than water so I should have been adding it slower with cooling, eventually superheated acidic methanol shot out, luckily not in my direction as I wasn't wearing goggles :O

4) I heated a flask of ammonium acid phosphate to fusion and then let the ammonia all come off (as best I could never got complete reaction) then I put the beaker on the patio paving slab only to have it shatter and spill the phosphoric acid... cleaning the slab woo

5) I heated the ammonium acid phosphate in the kitchen with the window and door open (ok I was like 14 here!) fumigating myself with ammonia (also used to regularly melt lead in a similar manner!)

and just for luck:

6) I made formaldehyde-thymol polymers on my bedroom windowsil in test tubes over the period of months... I later noticed my eyesight had deteriorated and a couple of years later I ended up getting glasses! Not that I wear them now thank god for 70+% water based contacts

kclo4 - 18-9-2008 at 16:23

1) Adding NaOH to fast to an Ammonium Salt is always an enjoyable mistake.
2) Never twist a ground glass stopper

3) Spilling I2 crystals, and then later getting them on you later
4) Leaving water in your condenser, in a place that freezes

5) Other obvious ones

Picric-A - 19-9-2008 at 02:13

haha i remember a accident i had,
i was preparing bromine by heating pool bromine tablets to decomp:
I think a runaway reaction happened becuase it was spewing out yellowish vapour everywhere! I dont know what the vapour was but sure as hell made me cough, eyes water and it stank out my lab for 3 days! :O
wont be trying that again lol!
I have done the NaOH/NH4NO3 accident aswell! smelt bad

Klute - 19-9-2008 at 03:18

On the most frightening chemical experience was H2S intoxication, which related in a thread here...

Thes econd must be adding ~15mL of diluted pirahna solution to a acid recovery bottle, containing mainly diluted aqua regia. I was cleaning some glass frits with carbon, dilute dthe pirahna when done, cleaned up the bench, emptied the pirahna into the acid recovery bottle, slide the sash donw completly (thank god), and when into the office to do some paper work. A few minutes after, one of the post grads working in the same lab arrives in a panic asking me what kind of reaction I was doing, and I answered none.
He then relate dto me how he entered the lab, heard a "shhh.." noise, turned around and saw my fume hood burst into a brown/red cloudy, whith liquid everywhere inside, and a very irritating smell comming out... He quickly opene dall the windows, closed the doors, and when to fetch me.
I was stunned to see acid dripping from all other the hood, the meatl support bars litteraly bubbling off, etc The Nox cloud was removed fairly quickly by the very effective ventilation (the hood was only a couple month old...), and after waiting a a few hours to get most of the fumes out, it was washing time.. I rinced the whole hood with a hose for 10min, then started disassembling all the equipement, tossing the damaged things, and washing the others... Even after sending over 200L water in the hood, the drops falling on my lab coat eat through it (and my sweater). Took we nearly a whole day toget everthing back on!

And during all that time I realized how lucky I was that:

-the bottle didn't explode (the lid was unscrewed obviously, the the pressure and foaming was justtoo powerfull) when I was working

-that I did take the sash down entirely (which alot of people don't do, now this story is told to make them think about it

) when I stopped working

-that another member of the lab didn't open the sash to get soemthing in the hood at the time it blew off

-that I had no other chemicals under the hood at the same time (imagine if I was distilling ether over benzophenone ketyl in a 5L flask!)

I was very surprised about the fact that the reaction kicked in nearly 10min after adding the acid, and that there was no heating or sizzling when it was added..

Apart from that (hopefully, other anecdotes are not even close to these two..), I did burn my hands with NaOH once, when unplugging a sink.... Re-used some gloves (no mor eleft), but put them on the wrong side, and realied it 30min after when my hands were starting to get painfull and my skin to wrinkle).

One of the most common source of concern in actually oil baths. They can heat up quite high, and are not always as stable as we think... Hopefully, I was never burnt, but did drop a flask containing pet ether in a 120°C oil bath, the bubbling (and splattering of hot oil) was pretty impressive... I put one the face shield and thick base-bath gloves and fished it out before too much vapors would have caused a fire hazard (gas-heated boiler only a few meters away...)

Of course,w e all learn from our mistakes, but i think the most important point to avoid them is to take your time and thinks things ahead... Saving a few seconds or minutes is not worth getting intoxicated, burnt or blinded!

woelen - 19-9-2008 at 10:10

One thing, which I recently did was adding solid NaH (yes, NaH, not NaOH!) to 65% HNO3. The spatula of solid went into the HNO3 and as soon as it touched there was a very brief sizzle and then a bright orange flash and BANG

The test tube cracked and droplets of HNO3 were sprayed around.

Nothing bad happened though, quantities were small (100 mg of solid plus 1.5 ml of liquid). I only was quite upset after this little accident.

kaviaari - 19-9-2008 at 13:27

Pouring water too fast to extinguish remains of sodium borohydride in a 1 l beaker, containing about 250 ml of reaction mixture in ether, was one of my greatest mistakes. For some reason I didn't think about the process and dumped in some 100 ml of cold water, well enough to get ether boiling and splattering all over the lab bench and, naturally, on me. The remains of borohydride in the solution reduced the pigments of my red t-shirt, giving an artistic reddish white shade to it. Now I'm a bit more careful with borohydride.

[Edited on 19-9-2008 by kaviaari]

chemrox - 20-9-2008 at 00:30

I was using AgNO3 to visualize pesticide spots and left the solution of ammonia and AgNO3 in the sprayer which had a ground glass joint. I forgot what we did exactly to clean up and avoid explosion but it involved welding gloves and nitric acid. More recently made up too much Pirhana and overran the container ...

Klute - 20-9-2008 at 07:00

What is the explosion hazard from AgNO3 and NH3? I don't remember hearing from this? We clean dark Ag stains with NH3 all the time... (though it's dilute I guess)

Fleaker - 20-9-2008 at 07:14

@Klute,

Supposedly ammoniacal solutions of silver nitrate (and less so, other silver salts soluble in ammonia) are to be avoided because of the formation of sensitive silver compounds (silver nitride seems most likely) dubbed fulminating silver. I've heard that they should be kept around for less than a few hours, then neutralized with acid (preferably HCl) to an insoluble precipitate. I follow this practice for silver nitrate ammonia system, but never for silver oxide or chloride dissolved in ammonia, I've stored that for months!

As for your experience with Caro's acid and aqua regia--shocking!! I don't understand it--was there heavy contamination of organics in the aqua regia. I've used 30% hydrogen peroxide (quite frequently) with hot, concentrated aqua regia solutions when dissolving Pt and never had a reaction like you describe. Granted Caro's acid is a different beast, but still, I know peroxide and aqua regia can be done safely.

ammoniacal silver

chloric1 - 20-9-2008 at 09:42

My silver waste was dissolved in ammonia and I forgot it for 3 days. Luckily, it was also exposed fully in midday sun so only brownish silver powder separated.

Klute - 20-9-2008 at 14:09

After relating my experience to several well-experienced chemists, they all told me HNO3 and H2O2 is an absolute no-no... Remeber this was a DILUTE solution of aqua regia, all the depleted (colorless to slight yellow) used acid been added, with at least 200-300mL water added to the bottle at the begging.. . I wasn't the onyl one using this bottle, it is highly psosible some un-diluted aqua regia was added on several occasions, but that's still far from concentrated.. and the pirahna (35% H2O2, 98% H2SO4) was aslo dilute dbefore adding tot he acid recovery bottle... So I would advise you to be extremly precautious with such mixtures! Better stick with HCl and H2O2?

Also, chances are there was traces of transistion metal salts present, as we work with these very often, and it's pretty common to attack traces of insoluble complexs with aqua regia from a glass frit for example. Maybe these could haev had something to do with the delayed reaction or soemthing, but it is still traces....

Picric-A - 21-9-2008 at 01:04

I remember i was cleaning a beaker with pirrana, it looked quite clean alredy apart from a few carbon smudges here and there so i slowly pippeted the pirrana in, at fist it just fizzed and then it started spraying steam and possibly H2SO4 everywhere!!! i still dont know what was in that

Klute - 21-9-2008 at 03:59

...organics?.. I know it is discussed fairly often, but pirahna should a kind of last-ressort thing..... It shouldn't be prepared in more than 5mL amounts IMHO, and diluted immediatly after use. I hear of more accidents using this solution than any other acid mixtures..

It doesn't tolerate even minute amounts of organics, even toilet paper will catch fire after a few seconds contact, I wouldn't want to see what happens if 5-10mL are spilled on a wood bench...

Picric-A - 22-9-2008 at 02:14

I once did a controlled addition of around 2 ml of Pirahna onto a small block of wood with a indent to support the liquid.
Nothing happened for the first few seconds until i noticed considerable bubbling... using a infrared thermometer the tem was recorded to be aorund 80degrees C... above the boilig point of H2O2 and shortly after recording the temp i heard (not saw... strange...) a small explosion!
now if that was on larger scale there must surly be a Peroxide explosion..

Jor - 25-9-2008 at 13:38

Today I wanted to fill a empty brown JTBaker bottle with 36% HCl. So I took my 5L container 36% HCl reagent grade.
I took a funnel, placed it on the bottle and placed a blower next to it pointing at the door to blow the fumes away. Now, I don't have experience with 36% HCl, only 32%, and certainly not 5L. When I opened it a HUGE cloud of HCl escaped and I started pouring. Half a liter done, I stopped and took a breath. COUGH COUGH. Then when the fumes were gone, I tried again quickly. When I was done, I had to clean up spils with bicarbonate (very hard to pour without splashing with 5L !). It was an experience I will remember as 2 words: COUGH COUGH!

Klute - 26-9-2008 at 02:43

I should use those PP hand pumps for gasoline to empty large containers of corrosives or toxics. They work very well. Keep one for each jerrican, as they are pretty cheap, and just rince them with water (for the HCl) by empying a 2L bottle tap water, followed by some dH2O or similar in the sink. A little dH2O in the compartiments won't ruin your acid next time you fill in a 1L bottle.

Hardly any fumes, no spills, and no tilting 5kg jerricans..

You also have the more elaborate versions:
Manual solvent pumps

epeters - 9-10-2008 at 11:47

here is one from personal experience: when drying parts that have been soaked in alcohols, do not place them in an oven until they are 100% dry, even if the oven temp is below flash points! i lit my parts on fire in a 100C oven once, because the fumes got back lit by the oven's heater elements.

Picric-A - 9-10-2008 at 12:11

No offence but you would have to be retarded to put anything flammable and volatile in an oven :O
ur lucky it only caught on fire and didnt turn into a small fab.
A recent mistake of mine, whilst filling a burette with HCl for a titration using a funnel i was watching the level increase in the burette, forgetting to constantly minitor the level in the funnel (constantly filling up the funnel), as you can probably guess, when it got to the top i stopped pouring the HCl but the funnel was full and spilt everywhere, runing my titration

easy to make mistake i guess... i need to be more carfull!

chief - 9-10-2008 at 15:16

==> Care to never over-heat Teflon, since many chemists died a miserable death from maybe 1breath-intake of the fumes (professor said so)
==> don't heat metal-powder with sulfur, may be very explosive,since at the ignition-point everything is already hot (Mg + S (powder), heated in a furnace, will make a big explosion)
==> beware of spurious Arsenic-content in metals, that dissolve in acid (eg. Zn), since the arsenic forms with hydrogen arsenic-hydrogen,_very_poisonous_ (more than HCN)

chemkid - 9-10-2008 at 17:49

I have done that too Picric (lcukily not with anything dangerous....yet)

Also, watch out for reactions that bubble a lot more than you think...

Chemkid

Picric-A - 9-10-2008 at 23:15

Chief- that is very true but nowerdays thigns like zinc flashing has almost all the arsenic removed due to health and sefety reasons ect...
Lab grade Zn granules/powder are pretty much free of arsenic.
But good warning- always best to be on the safe side...

cnidocyte - 31-1-2011 at 13:24

A lesson I just learned. Never turn on the stirrer if the solution is already boiling/bumping. I was distilling HCl just there and the solution was bumping. I had a magnetic stirrer in there and decided to turn on the stirrer then WHOOOOSHHHH, the still head flies off and the flask spits out boiling hot hydrochloric acid, some of which gets in the hot oil bath which causes the whole thing to erupt. Its amazing I escaped all that without any 3rd degree burns. I'll never make this kinda mistake again.

Magpie - 31-1-2011 at 13:35

Quote: Originally posted by chief

==> Care to never over-heat Teflon, since many chemists died a miserable death from maybe 1breath-intake of the fumes (professor said so)
==> don't heat metal-powder with sulfur, may be very explosive,since at the ignition-point everything is already hot (Mg + S (powder), heated in a furnace, will make a big explosion)
==> beware of spurious Arsenic-content in metals, that dissolve in acid (eg. Zn), since the arsenic forms with hydrogen arsenic-hydrogen,_very_poisonous_ (more than HCN)

Chief those are some very good warnings! I occaisionally work with ores (Cu, Zn, Au, etc) and usually do dissolve them in acid or reduce them in a furnace. So it is indeed wise to do ore processing in a hood. You never really know what they contain, and very often do have arsenic.

I have proabaly been a little careless with heating Teflon also, not really realizing how lethal this could be. Thanks.

Lambda-Eyde - 31-1-2011 at 13:46

Wear gloves and safety goggles at all times. It's amazing I haven't lost my eyesight or suffered from serious burns yet.

Make sure you have several types of thick gloves. Nitrile is my favourite, but it does NOT protect against e.g. concentrated nitric acid. 99% HNO<sub>3</sub> will ignite nitrile, not a scenario you would like to witness first hand (pun intended

).

Never ever add boiling stones after you have heated up your reaction mixture. I learned that the hard way when distilling acetone from a solution of benzoic acid. I don't want to think about how it could have been if it was a strong acid or something toxic.

Squirt bottles! Buy at least 3 of them. One with distilled water, one with dilute acetic acid and one with a sodium (bi)carbonate solution. If you work with bromine I recommend getting one for a sodium thiosulfate solution as well. These things are extremely handy to have standing around. One for acetone is extremely handy for cleaning purposes.