Sciencemadness Discussion Board

What are most dangerous toxic chemicals you are comfortable handling in your home lab?

MidLifeChemist - 28-11-2020 at 12:24

I'm wondering where people draw the line regarding the most toxic chemicals they are comfortable handling in their home lab, and what, if any additional precautions they take other than the normal PPE (goggles, gloves, lab coat).

I was able to recently set up a home lab in my garage now that I have a larger space. But I don't have a fume hood, and I have other family members in the house. I thoroughly read the safety data sheet on all chemicals I have to understand the risks.

Here's the most toxic chemicals I have now:

- Top of the list out the chemicals I use is (imho) Potassium Dichromate because of risks from several routes - 130mg oral LD50 (rat, per kg), OSHA hazard ids are acute oral 3, acute inhalation (dust) 2, carcinogen 1A, organ toxicity 1

For hazard ids, lower number means higher risk. More info here: https://www.osha.gov/Publications/OSHA3844.pdf

Other top carcinogens I have & use include:

- Vanadium Pentoxide - 300mg LD50, acute oral 4, inhalation 4, carcinogen 2, organ 1
- Nickel sulfate - 264mg LD50, acute oral 4, carcinogen 1A

I also have CoSO4 and SbCl3 which are slightly less dangerous based on safety data sheets.

Topping my acute toxicity list of chemicals I use are:

- Sodium fluoride - 31mg to 100mg LD50, acute oral 3; this is the most acutely toxic chemical I have
- Lead nitrate - 93mg LD50, acute oral 4, inhalation 4, organ 2
- Barium chloride - 115mg LD50, acute oral 3, inhalation 4
- Sodium sulfide - 250mg LD50, acute oral 3, acute dermal 3, included because of the risk of producing highly toxic H2S with acid

I'm comfortable with what I have, but the following are chemicals I'd like to have & use but I'm holding off on because of their toxicity and overall nastiness of symptoms, and my comfort level with them in my current space isn't quite there yet:

- Mercury II chloride - 26mg LD50, acute oral 2, acute dermal 1, organ toxicity 1
- Sodium arsenite - 41mg LD50, acute oral 2, dermal 2, inhalation 3, carcinogen 1A
- Thallium chloride - 35mg LD50, acute oral 2, inhalation 2, organ toxicity 2
- Cadmium nitrate - 100mg LD50, acute oral 3, dermal 4, inhalation 4, carcinogen 1A, specific organ 1
- Sodium selenate / selenite - 2mg to 7mg LD50, acute oral 1, acute inhalation 3

So what are the most toxic chemicals that other SM members have? Where do you draw the line with respect to what chemicals you will store and use in your home lab? And do you take additional precautions with your most toxic chemicals?

Looking forward to reading the responses...


[Edited on 11/29/2020 by MidLifeChemist]

Fluorite - 28-11-2020 at 12:54

the most toxic chemicals I have: sodium chromate, sulfur monochloride, and nitric acid
Why toxic chemicals are stable? Chromic acid is stable but carcinogenic af but permanganic acid and ferric acid are less toxic but unstable :(
Sodium fluoride is very toxic? I thought it's safe to touch https://m.youtube.com/watch?v=scN6_LItWqo
I need to understand what acute oral, dermal, inhalation means :/

Fyndium - 28-11-2020 at 13:46

Are the amounts per kg or total dosage? Because sodium fluoride lethal dose is 7-10 grams according to Wiki. This puts it in the range of caffeine, hence you can handle it pretty casually with common sense. Brits got it on poisons list, though, so it should be more toxic than a cuppa, at least. (pun for the nanny banny state)

V2O5 is also available in ceramics and artisan stores sold by the bag, so if it's actually almost as toxic as cyanide, I find there a big how?

I don't actually handle toxic stuff at all unless I have access to my exhaust connected fume hood. With that, I feel much safer handling even the more toxic stuff, unless it has risk of blowing up, splashing or causing any sudden runaways or stuff like that. And yeah, sulfuric acid is toxic too, but it's not volatile and is easily decontaminated, so you get the point on toxicity.

Toxicity has little to do with stability. It has more to do with our metabolism, which is just sensitive to some stuff. There are ubiquitous amounts of molecules that are very unstable and at the same time basically nontoxic.

Some toxic stuff are volatile or dust a lot so they can be breathed. Smaller the molecule, the easier it passes through the skin, hence dermal exposure can provide fatal, see cyanide solution. Oral toxicity is as invasive way of getting stuff into your body, but metabolism states if it's absorbed. Metallic mercury and non-reactive, non-water-soluble stuff are generally sparsely absorbed. Cyanide salts hydrolyse with water already, and in contact with stomach acid will make HCN, and the rest is history.

Sometimes it is stated that if something toxic is ingested, one should not be induced vomiting. I wonder if this is less harmful than puking it out as fast as possible, meanwhile it is absorbed in the body causing systemic damage.

Fun fact, hydrofluoric acid does not state instructions in case it's ingested. It's unnecessary by that time.

HydrogenSulphate - 28-11-2020 at 15:04

Quote: Originally posted by Fyndium  
Are the amounts per kg or total dosage? Because sodium fluoride lethal dose is 7-10 grams according to Wiki. This puts it in the range of caffeine, hence you can handle it pretty casually with common sense. Brits got it on poisons list, though, so it should be more toxic than a cuppa, at least. (pun for the nanny banny state)

V2O5 is also available in ceramics and artisan stores sold by the bag, so if it's actually almost as toxic as cyanide, I find there a big how?

I don't actually handle toxic stuff at all unless I have access to my exhaust connected fume hood. With that, I feel much safer handling even the more toxic stuff, unless it has risk of blowing up, splashing or causing any sudden runaways or stuff like that. And yeah, sulfuric acid is toxic too, but it's not volatile and is easily decontaminated, so you get the point on toxicity.

Toxicity has little to do with stability. It has more to do with our metabolism, which is just sensitive to some stuff. There are ubiquitous amounts of molecules that are very unstable and at the same time basically nontoxic.

Some toxic stuff are volatile or dust a lot so they can be breathed. Smaller the molecule, the easier it passes through the skin, hence dermal exposure can provide fatal, see cyanide solution. Oral toxicity is as invasive way of getting stuff into your body, but metabolism states if it's absorbed. Metallic mercury and non-reactive, non-water-soluble stuff are generally sparsely absorbed. Cyanide salts hydrolyse with water already, and in contact with stomach acid will make HCN, and the rest is history.

Sometimes it is stated that if something toxic is ingested, one should not be induced vomiting. I wonder if this is less harmful than puking it out as fast as possible, meanwhile it is absorbed in the body causing systemic damage.

Fun fact, hydrofluoric acid does not state instructions in case it's ingested. It's unnecessary by that time.


I believe that phenol is also on the poison list in 'Banny Nanny' state, which is probably why it is nigh on impossible for a private individual residing in 'Banny Nanny' state to buy it (although podiatrists are able to procure it). I mean, yes, phenol can potentially be quite harmful (for example, inflict burns via the denaturation of proteins), but if one treats it with respect, understands its characteristics and uses the usual PPE, it is safe to handle. I can think of far, far more toxic chemicals that are tricky to handle without adopting special measures. HCN, HF or fluorine gas to name a few (I would not touch such chemicals with a bargepole, even if it were possible for me to obtain them!). Thankfully, phenol is not too difficult to synthesise.

As for NaF- they have no qualms putting it in toothpaste!

[Edited on 28-11-2020 by HydrogenSulphate]

j_sum1 - 28-11-2020 at 15:19

My willingness to handle dangerous chemicals has more to do wiyh my knowledge and experience than anything else.

I am ok with chlorine, bromine and NOx. And that is without a fume hood. But I know how to control production rate, scrub effectively, and pack down without releasing uncontrolled amounts of gas.
Similarly, H2S does not strike fear into me. But I am extremely reluctant to handle HCN and cyanides in spite of HCN having roughly the same toxicity. That is simply because I know a lot more about H2S and have some experience with its properties.

Oral ingestion is easy to mitigate against. It is the surprises that come from inhalation that worry me more. So, I really don't have issues with Cr(VI). That said, I am usually using very small amounts. I think quantity control is the most overlooked safety measure in all OHS literature.

I do have Hg, As compounds and some Tl. I have not touched them and may not for some time. This is from lack of knowledge. I don't know the full spectrum of properties and risks. Therefore, I don't feel equipped to work with them.

So, that's where the line is for me. More related to my knowledge than to the materials themselves.

(And yes, I have been caught out a couple of times. Greater understanding is a good thing.)

Fyndium - 28-11-2020 at 15:44

Quantity control. Pressing words. When scaling up reactions, stuff can happen, and when it gets out of hand, it's a totally different thing when it happens on 10mL scale than on 10 000mL scale.

Individual control on stuff is more of common safety and then a security matter. There are stupid people who mishandle the stuff and cause accidents to themselves and others, and then there are bad people who intent to cause accidents to others. For the motivated, most things can be circumvented somewhat easily, though, but restrictions appears to have effect on idiots.

Lion850 - 28-11-2020 at 21:01

I very much agree with j_sum1's comments.

I try to think ahead a bit more and avoid chemicals I am not comfortable with. I have small quantities of mercury salts but I do not intend to do anything with them. I was at one point keen on making arsenic triiodide, but will avoid arcenic for now. Also not keen on thallium. I have some uranyl acetate, and like the idea of making uranium salts, but I am not ready for it.

I avoid cyanides. I dont want to make bromine as I dont know how to store it (never made ampoules).

I am respectful of H2S and NOx fumes but not scared - these are smells I fondly remember from my lab when I was a teenager in the late '70s!

artemov - 28-11-2020 at 21:36

Have made potassium dichromate, lead acetate, nickel sulfate/chloride.

Have made hydrazine -> hydrazine sulfate -> potassium azide (which I destroyed almost immediately)

Have generated chlorine from TCCA and HCl.
Wanted to make bromine for fun, but decided not to cos I have no use for it and I doubt I can store it properly.

Will not deal with toxic gases like HCN, phosgene (no fume hood) or any mercury, thallium, arsenic salts.

B(a)P - 29-11-2020 at 01:03

Quote: Originally posted by MidLifeChemist  
I'm wondering where people draw the line regarding the most toxic chemicals they are comfortable handling in their home lab, and what, if any additional precautions they take other than the normal PPE (goggles, gloves, lab coat).


[Edited on 11/29/2020 by MidLifeChemist]


No matter what I am doing I always put on eye protection, a coat and nitrile gloves when I enter the lab. If I am doing anything that might generated toxic fumes I will wear a full face respirator with appropriate cartridges.

My most toxic compounds are currently in the lab are:
Mercury and it's nitrate
Cadmium and it's nitrate
Hydrazine sulfate
Benzo alpha pyrene

There is nothing I won't work with, but I spend a lot of time researching and purchasing equipment before I proceed with a synthesis involving toxic precursors of products.

Heptylene - 29-11-2020 at 01:49

These are some things I don't want to handle in my lab:
- Anything explosive is out of the question.
- Highly toxic gasses like phosgene, HCN, or gasses that would cause a major nuisance to the neighbors like H2S. NO2 or Cl2, Br2 are much less problematic in comparison.
- Beryllium, Thallium, Mercury unless the reaction is quantitative. This is because I don't want to have waste from these metals.
- Fine powders of carcinogens. I once transfered some potassium dichromate to a new bottle and I am glad I did it outside with a dust mask because that stuff gets everywhere!
- Lacrymatory substances like esters of chloroacetic, bromoacetic acid, benzyl chloride, etc.

HydrogenSulphate - 29-11-2020 at 04:42

I strongly practice the concept of atom economy, aka recycling. As such, I don't produce disposable wastes, aside from aqueous salts of low value and low toxicity (calcium/sodium chloride, calcium/sodium acetate, calcium/sodium sulphate, and the like) that can safely be poured down the drain. Transition metal compounds are recycled: by applying a little bit of chemical 'wizardry' it is easy to interconvert between soluble and non-soluble forms of a transition metal compound, and to change the oxidation state to the desired one.
Volatile aromatic and aliphatic organics are purified and recaptured by distillation and condensation. Vapours are condensed back into a liquid and collected into a GL45. By practicing on a microscale (all of my syntheses can be comfortably accommodated in a 100mL round bottom flask) and recapturing vapours by distillation and condensation, little volatile organics are lost to the atmosphere.

[Edited on 29-11-2020 by HydrogenSulphate]

[Edited on 29-11-2020 by HydrogenSulphate]

unionised - 29-11-2020 at 05:43

I have read- and I have no reason to doubt it- that brazil nuts have a relatively large radium content; much more than most foodstuffs.

If I had a good alpha counter I might think about buying a kilo of nuts, ashing them, reducing hell out of the ashes with sodium carbonate and charcoal at bright red heat.
Rinse that product with water to remove sodium sulphide etc.
Then leach with acetic acid and add chromate.
That should precipitate barium chromate reasonably selectively.
It should contain a few dozen becquerels of radium.
Would that count as "working with radium in a home lab"?
Would anyone be worried about the radium, given that it was delivered as food?

My point is that , as Paracelsus pointed out, it's the dose that makes a poison.

itsallgoodjames - 29-11-2020 at 15:03

The most toxic/carcinogenic chemicals I have and use are:
- ammonium dichromate
- potassium dichromate
- mercuric nitrate
- mercuric chloride
- uranyl nitrate
- sodium diuranate
- sodium azide
Scary, though not as bad as the rest:
- very dilute (3%)hydrofluoric acid

MidLifeChemist - 29-11-2020 at 17:34

@flourite - thanks for your reply. I added a link to osha.gov to my post to help with your questions.

@Lion850 - I'd like to do some Uranyl experiments. Uranyl acetate is $160 for 25grams here in the US. So maybe someday. Also - there are lots of videos on how to make an ampule, it is fairly easy, you should try making one (without the Bromine in it).

@artemov - did you mean phosgene or phosphine? Huge difference in toxicity! (factor of 25)

@B(a)P - thanks for your reply. Out of curiosity, where is your lab, is it connected to or separate from your primary residence? It is always interesting to see how/where people set up their labs.

@Heptylene - thanks for your reply. Did you mean phosgene or phosphine? Regarding dust, yeah I have the same issue, I have to transfer chemicals into bottles outside with a dust mask to avoid inhalation. I have some Cr2O7 to transfer and I'm not looking forward to it.

@itsallgoodjames - thanks for the reply. Where did you get the uranium compounds from, have you done anything interesting with them yet?

B(a)P - 29-11-2020 at 18:43

Quote: Originally posted by MidLifeChemist  
@flourite - thanks for your reply. I added a link to osha.gov to my post to help with your questions.

@B(a)P - thanks for your reply. Out of curiosity, where is your lab, is it connected to or separate from your primary residence? It is always interesting to see how/where people set up their labs.



My lab is separate from my dwelling.
I also have access to a lab through work.

itsallgoodjames - 29-11-2020 at 18:46

United nuclear. I haven't done anything interesting with them yet, I intend to turn the uranyl nitrate into a uranium and titanium* (maybe titanium, maybe some other metal, the point is to prevent corrosion) alloy at some point, though that's pretty much at the bottom of my priority list right now. The sodium diuranate is just a collection piece, I keep a small sample of it in the uranium spot on my element collection, until I make said uranium metal. Uranium chemistry is neat, it's just terrifying, given you have something that has all the dangers of working with soluble mercury salts, and it's also radioactive. That's most of the reason I haven't really done much with it.

Clear_horizons_glass - 29-11-2020 at 20:33

If I have to really clean some quartz, I use Hydroflouric Acid. But only under a fume hood with tripple gloves and a vinyl apron with lots of cover. I only do it as a last resort.

Another rule I follow is I never heat up any glass that has residue of an unknown origin. Many people don't consider how dangerous this can be.

artemov - 29-11-2020 at 21:21

Quote: Originally posted by MidLifeChemist  

@artemov - did you mean phosgene or phosphine? Huge difference in toxicity! (factor of 25)


Phosgene ...

I have a bottle of Red P stored in a box with calcium chloride dessicant. Once in a while I will open up the bottle to take a look at the Red P. There is a strange smell though ... :o

MidLifeChemist - 29-11-2020 at 21:54

Quote: Originally posted by artemov  


Phosgene ...

I have a bottle of Red P stored in a box with calcium chloride dessicant. Once in a while I will open up the bottle to take a look at the Red P. There is a strange smell though ... :o


Well, if you want the smell to go away, either stop heating your Red P up with hydrogen gas, or heat all of it up with an excess of hydrogen, in a small enclosed room. Either way, that bad smell will go away...lol

[Edited on 11/30/2020 by MidLifeChemist]

teodor - 30-11-2020 at 02:32

I am quite comfortable with CrO3 derivatives (e.g. dichromates), V2O5, Ni, Ba, Sb, sulfides. I don't know why do you consider them as "toxic" - we don't eat those chemicals isn't it? Pb is something which requires a bit more attention, but still is "quite manageable group" for me.
On the other hand compounds of Hg, As, Tl are really toxic from my point of view.
And I would be really scared to work with alkali cyanides. May be even too scared to work safely with them. Mostly because they really have a bad reputation and so I have no idea what to expect from them.
So I see the most of the problem is my attitude based on those chemical properties and subjective factors. Not IDLH number.
A week ago I handled a hot nitrate salt solution with HNO3 residue. It had such kind of vapours which immediately blocks your breathing, you even don't control it. I would say 100 ml of such hot solution can have more impact on your health than bucket of dichromate on your table.
About gases: I would definitely avoid CO. But I am quite comfortable with Cl, NO2. And I am working with H2S with some precautions.

Most toxic? I often bend FEP hoses. Near the melting point they produce some toxic vapours, I think it could contain HF. It cause very unpleasant sensation in the throat. So, if it was HF probably it is the most toxic one. With proper ventilation/gasmask I am quite comfortable.


[Edited on 30-11-2020 by teodor]

itsallgoodjames - 30-11-2020 at 08:41

My concern with chromates and dichromates is how carcinogenic they are. One might not even know they have inhaled some dichromate dust, and that's concerning to me. I'm actually more comfortable working with cyanides (though not HCN), as they have mostly acute effects, so they'll give me cyanide poisoning if I'm stupid, but they won't give me cancer 20 years down the line. Maybe a bit of an irrational fear, but heavy metal salts scare me.

Also O3 and CO are nasty. I refuse to work with ozone and carbon monoxide

[Edited on 30-11-2020 by itsallgoodjames]

teodor - 30-11-2020 at 09:11

Quote: Originally posted by itsallgoodjames  
My concern with chromates and dichromates is how carcinogenic they are. One might not even know they have inhaled some dichromate dust, and that's concerning to me.


Are you assuming it is more carcinogenic than a smoke of a cigarette ? By the way, some relative carcinogenic scale would help with everyday chemistry, at least which dust/vapours is better to collect first. When everything is "carcinogenic" it becomes totally misleading.

Quote: Originally posted by itsallgoodjames  

I'm actually more comfortable working with cyanides (though not HCN), as they have mostly acute effects, so they'll give me cyanide poisoning if I'm stupid, but they won't give me cancer 20 years down the line. Maybe a bit of an irrational fear, but heavy metal salts scare me.


I can work with small quantities of HCN because I have a full control of (small quantity) generation and I am using a fume hood, I know where it is contained to neutralise it. And I never contact with it in such case. Also I can recognise its presence by smell. But any powder assume some weighing, risk of instrument/table/whatever contamination, opening/closing manipulation of a bottle and in this case CN- scares me, it is like I have a less control about possible cases and consequences and no ability to detect it with my senses, but probably it is just lack of experience.
I think you underestimate the acute effect, do you remember the thread of knock-out potential? I think it is much more dangerous aspect than probable cancer. Most of cases of cancer with people I know has no roots in amateur chemistry. That means there is no direct connection of carcinogenic effect of mild carcinogens and a cancer itself.

Quote: Originally posted by itsallgoodjames  

Also O3 and CO are nasty. I refuse to work with ozone and carbon monoxide


I never thought about O3 as a toxic substance. At least at those concentration which could be produced in a lab by some electric discharge.



[Edited on 30-11-2020 by teodor]

itsallgoodjames - 30-11-2020 at 10:29

O3 really is quite toxic. The OSHA limit for ozone in workplaces is something like 100ppb. Not 100 parts per million, 100 parts per billion. For reference the limit for hydrogen cyanide is 40ppm and Carbon monoxide is 50ppm. Not that OSHA limits are a great way of Ozone is remarkably toxic. I guess it's a good thing it has such a potent odour. if you have any doubt, look at it's fire diamond:

Screenshot_20201130-132909_Chrome.jpg - 22kB

teodor - 30-11-2020 at 10:39

Are home ozonators (like https://www.amazon.com/customerpicks/Explore-ozone-machines-...) really intended to saturate your house with something with OSHA 100ppb?

[Edited on 30-11-2020 by teodor]

The idea of my previous post is that numbers like IDLH or OSHA could be misleading without some details including mechanism of action. If one try to handle chemicals only according to these numbers he will present real danger for the society. I can't see any reason why HCN generator should be considered more dangerous than O3 generator if I look only on those numbers.

As I mentioned before, according to IDLH, HBr is 2 times more dangerous than HCN.


[Edited on 30-11-2020 by teodor]

MidLifeChemist - 1-12-2020 at 09:04

@B(a)P - you are lucky to have a separate lab, that is great. Did you ever make the WFNA?

@Clear_horizons_glass - what strength is your HF?

@Teodor -it is not my decision to call these chemicals "toxic", I am simply using the words defined by the CDC and OSHA in my country (for better or worse). Btw, OSHA does rank all chemicals by their risks from acute and long term exposures, I looked up the values and you can see them in my original post. For example, for C2O7, level "1A" is the highest level for a carcinogen. But I do think comparing it to cigarettes is a good question.

@itsallgoodjames - yeah, my main concern is long-term & repeated exposure from dusts and powders that I am not aware of, not eating any of the chemicals. This may change if I can improve my clean-up procedures & air-flow.

Everyone - since we are talking about various gases like HCN, H2S, HBr, etc. - I found this very interesting page which lists IDLH
values / estimates (Immediately Dangerous to Life or Health) for a large number of compounds. Like @itsallgoodjames mentioned, the level for ozone is much lower than other gases mentioned in this thread.
https://www.cdc.gov/niosh/idlh/intridl4.html

[Edited on 12/1/2020 by MidLifeChemist]

teodor - 1-12-2020 at 09:28

Quote: Originally posted by MidLifeChemist  

Everyone - since we are talking about various gases like HCN, H2S, HBr, etc. - I found this very interesting page which lists IDLH
values / estimates (Immediately Dangerous to Life or Health) for a large number of compounds. Like @itsallgoodjames mentioned, the level for ozone is much lower than other gases mentioned in this thread.
https://www.cdc.gov/niosh/idlh/intridl4.html


I just repeat what I said before - without additional study this table is totally misleading.
According to this table these compounds have approximately the same level of danger: Arsine, Bromine, Chlorine Dioxide, Iodine, Ketene, Nickel Carbonyl, Ozone, Phosgene.
And, according to IDLH, any of them is 5-10 times more dangerous than fluorine.

I never heard about deadly accident of ozone poisoning in a home lab. But cases of deadly accidental poisoning with cyanide in a home lab are well-known, probably the case of Alan Turing is the most notable one. The same with Ketene vs Phosgene. The latter have many souls on its account while the former has virtually no reported cases.

Was one aware about 10 ppm OSHA PEL of acetic acid when he was making his salad? So, there is should be no difference to make it with iso-propyl bromide or benzene next time, according to OSHA.

Edit: I personally often use this table as well as OSHA PEL to plan general order of my experiments. This allow me to postpone working with some dangerous/nasty substances until I will have a better equipment/techniques. And I totally agree with what B(a)P said. One should study all available information as much as possible and postpone doing those things his lab is not suitable yet.


[Edited on 2-12-2020 by teodor]

MidLifeChemist - 2-12-2020 at 10:37

I think it is also interesting to look at industrial accidents, although it is true they are using chemicals at a much, much larger scale.

For example, there have been many deaths / accidents in the USA involving Na2S or NaHS. It helps remind me to be careful with my Sodium sulfide (I have a 1lb bottle) and that mistakes can happen.

https://www.csb.gov/csb-releases-safety-bulletin-warning-of-...

And if you want to look at non-industrial accidents, I think death from trimethylsilyldiazomethane tops the list.

[Edited on 12/3/2020 by MidLifeChemist]

Piroz - 22-12-2020 at 16:20

I had around 15ml of liquid N2O4/NO2 (I had because after months it destroyed jar cap 5 times and converted into iron nitrate, the rest in flasks turned into blue liquid- maybe N2O3?), now I have few grams potassium cyanide, sodium cyanide, nickel sulfate and few others.

Cou - 24-12-2020 at 17:25

The most toxic chemical I've handled is probably bromoethane.

vano - 1-1-2021 at 06:49

The most toxic compound I had, was dimethylcadmium.

roXefeller - 1-1-2021 at 07:45

Anyone know what melgar likely died from? It looks like he probably unpacked some chemicals from storage shortly before his death.

Bedlasky - 1-1-2021 at 07:59

The most toxic compound I ever worked with is probably thallium nitrate (but as a dilute solution, I never worked with solid stuff).

The most toxic things I have are:

Potassium dichromate

Small amount of mercury (elementar mercury isn't much toxic, it's very unreactive and evaporate incredibly slowly at room temperature, but it can be easily converted in to toxic mercury compounds)

Sodium selenite

Vanadium pentoxide

Ammonium fluoride

Small amount of diethylenetriamine and his pentamethyl analogue

Diethyleneglykol

When I work with inorganic, I am comfortable to work with most of chemicals. I dare not to work with cyanides, asrenic and his compounds and hydrofluoric acid (at least for now). I don't want to work with some very toxic gases like cynogen, HCN, PH3, AsH3, H2Se etc. But I am comfortable to work with small amounts of H2S. I don't feel to make elementary bromine - honestly, I don't have good glasware and fumehood, so I simply cannot make it. Bromine fumes like a hell and I live in housing estate, so this isn't good idea. If I really need some bromine, I'll make fresh bromine water just before I'll need it. I do mostly inorganic, so water and KHSO4 or something like that isn't problem in most cases. I don't work with large amounts of chlorine from the same reason - lack of good glassware for working with large amount of gases and living in housing estate.

I am not comfortable with working with some organic stuff, because I have just basic knowledge about organic chemistry. I also don't have space and money for buying various apparatus, magnetic stirrers etc., so I am also very limited in this field. I also don't know where to buy lots of useful organic chemicals, this is another problem.

[Edited on 1-1-2021 by Bedlasky]

vano - 1-1-2021 at 09:02

Quote: Originally posted by Bedlasky  
The most toxic compound I ever worked with is probably thallium nitrate (but as a dilute solution, I never worked with solid stuff).

The most toxic things I have are:

Potassium dichromate

Small amount of mercury (elementar mercury isn't much toxic, it's very unreactive and evaporate incredibly slowly at room temperature, but it can be easily converted in to toxic mercury compounds)

Sodium selenite

Vanadium pentoxide

Ammonium fluoride

Small amount of diethylenetriamine and his pentamethyl analogue

Diethyleneglykol

When I work with inorganic, I am comfortable to work with most of chemicals. I dare not to work with cyanides, asrenic and his compounds and hydrofluoric acid (at least for now). I don't want to work with some very toxic gases like cynogen, HCN, PH3, AsH3, H2Se etc. But I am comfortable to work with small amounts of H2S. I don't feel to make elementary bromine - honestly, I don't have good glasware and fumehood, so I simply cannot make it. Bromine fumes like a hell and I live in housing estate, so this isn't good idea. If I really need some bromine, I'll make fresh bromine water just before I'll need it. I do mostly inorganic, so water and KHSO4 or something like that isn't problem in most cases. I don't work with large amounts of chlorine from the same reason - lack of good glassware for working with large amount of gases and living in housing estate.

I am not comfortable with working with some organic stuff, because I have just basic knowledge about organic chemistry. I also don't have space and money for buying various apparatus, magnetic stirrers etc., so I am also very limited in this field. I also don't know where to buy lots of useful organic chemicals, this is another problem.

[Edited on 1-1-2021 by Bedlasky]


Potassium dichromate is often considered very dangerous. For some reason I never thought so, the main thing is not to inhale its dust. Dropping on the hand and similar actions are acceptable to me or spilling the solution on the skin. Also I do not have fumehood so I'm forced to let everything go in the atmosphere.

valeg96 - 1-1-2021 at 09:26

Potassium dichromate is banned at my university for educational use. Only research laboratories are allowed to use it.

Actually, anything with H340, H350 and H360 is banned within educational labs; they can be stored, but not used.

I'll leave it to your imagination to guess how sad some laboratories are. You got these professors who used to carry out synthetic labs where they made azo dyes, Ni and Cr complexes, and all they can do now is soap making and Al salts, or oxalates.

vano - 1-1-2021 at 09:46

Valeg it is very bad. I started studying at the university this year. It is considered to be the best university in my country, but I have not seen a single flask yet. There were incredible reagents left in the school after the collapse of the Soviet Union. There are plenty of reagents, but I have never seen any reaction, so I try to get as much compound as possible. I also find that chemistry around the world has become very weak. Compared to old German and Soviet sources, after 20 centuries such large-scale studies in chemistry no longer took place. I can not understand why they want compounds if dont use them. If I had the reagents that were in my school, I would now be a professor of practical chemistry :D

Fyndium - 12-1-2021 at 13:49

Btw, how are extremely toxic reagents like dimethylmercury handled in professional labs? In a negative pressure glove box? How do they decontaminate the equipment after use?

medchemist - 17-1-2021 at 04:07

Quote: Originally posted by Fyndium  
Btw, how are extremely toxic reagents like dimethylmercury handled in professional labs? In a negative pressure glove box? How do they decontaminate the equipment after use?


One of my profs used to handle incredibly potent cytotoxic compounds that are used to make antibody-nanoparticle-cytotoxic type molecules that are designed for targeted cancer chemotherapy.

Said cytotoxic compounds were so potent that less a milligram would likely be fatal.

He said they used a glovebox but I'm not sure if it was neg pressure, but there were very stringent measures taken in their handling, particularly in decontamination.

As for dimethylmercury there's the added danger of it's volatility, so negative pressure is a bad idea here as it'll cause more to evaporate. I would think that it is largely handled diluted in a suitable solvent and syringed from bottle to flask to minimise vapours from escaping and using certain gloves as it is able to permeate many materials but this is a guess, I have never, and will never, use that stuff.

Xanax - 19-5-2021 at 02:47

I extracted ricin and abrin from beans in my kitchen. Began to vomiting blood, and had bloody faeces. Think it's a few milligram is deadly dose.

Fyndium - 19-5-2021 at 03:04

Extracted ricin in my kitchen? Sounds like a premise of a detective story. :D

Quote: Originally posted by medchemist  
As for dimethylmercury there's the added danger of it's volatility, so negative pressure is a bad idea here as it'll cause more to evaporate.


Do you say that sub-millibar negative pressure would increase it's volatility to a substantial degree?

Antiswat - 26-6-2021 at 04:11

reading toxicity based on lethal dose is silly imo. ive tried being poisoned with fluorides (through welding smoke) and its quite nasty stuff. but theres so many places you get exposed to it, its an accumulative poison. mercury would def be the worst of accumulative poisons causing very rapid and irreversible brain damage, i believe exactly mercury is what killed my grandmother through faulty medicinal practices. just metallic mercury particles inserted near growing brain neurons will cause them to collapse roughly 3 times as fast as they grow, "2 drops of organic mercury" video sheds light on how nightmarish it really is. i do have half a kg of mercury that i keep locked up however. i also have some lead acetate i keep locked up along with the mercury
i also have a bottle of potassium chlorochromate, it constantly generates chlorine gas from the HCl in there, so if youre in for that kind of a rollercoaster you can have a try, cranking it open my buddy called it "instant swimming pool"

i also have some vials of ammonium sulfide, H2S is super toxic.
seeing selenium compounds is listed as toxic, i have H2SeO4 that i ironically use to avoid mercury toxicity

S.C. Wack - 26-6-2021 at 12:11

Quote: Originally posted by roXefeller  
It looks like he probably unpacked some chemicals from storage shortly before his death.


The most dangerous chemicals are those you don't know you have. I had a fun experience with carbon that might be mentionable.

I bought some bone char for some experiments that didn't work; the package said 0-16-0 (NPK) as though it was sold as a soil amendment, but it wasn't sold to me in that way, and it didn't come to me from that seller on the label. (neither party offers any charcoal now) Now I considered it for decolorizing (gallic acid from nutgalls) because of the somewhat granular size. It didn't work for decolorizing either. Maybe it ought to be washed with HCl...fwoosh...instant H2S...A truly staggering amount of gas, bubbling out for a long time too. There is absolutely no indication that this isn't virgin charcoal otherwise. H2S is fine when you're expecting it...

It seems that this is spent carbon which had been used to desulfurize something somewhere. No one wants to admit this for some reason.

I've mentioned a similar experience with pottery grade BaCO3 which was in fact *heavily* contaminated with BaS.

[Edited on 27-6-2021 by S.C. Wack]

Mateo_swe - 2-7-2021 at 23:04

Is Ozone really that bad as said earlier in this thread?
I mean ozone generators sold just specify nobody should not be in the room while the unit is running and one should open a window after to air out the ozone smell.
I have done lot of experimentation with high voltage and tesla coils in the past where the ozone smell was strong when running the high voltage.
I didnt feel any bad effects breathing the air even it did smell ozone.

Bedlasky - 2-7-2021 at 23:16

I had lung pain maybe one hour after breathing air with relatively low concentration of ozone.

Mateo_swe - 3-7-2021 at 00:23

Very strange i didnt get the same effects.
I know ozone smells at very low concentrations but i must have got some when being in that room playing with high voltage.
Maybe the concentrations are lower than one think as low concentrations also smell.
Wikipedia says as little as 0.1 ppm in air smells.
It also says:
All portable indoor air cleaning devices sold in California must be certified by the California Air Resources Board (CARB). To be certified, air cleaners must be tested for electrical safety and ozone emissions, and meet an ozone emission concentration limit of 0.050 parts per million.

Thats extremly low levels.
Im going to try an homemade ozone generator in some chemistry experiments (i know peroxides and explosion risks) and the Ozone generator unit is specified at 48 grams/hour.
If ozone levels over 0.050 parts per million is dangerous i will be dead just turning this device on for a couple of seconds.
Maybe one must be in high concentrations for a long time for it to be that dangerous as they say.
Also ozone decomposes fast in temperatures over 0°C, at least in solutions.
I wonder why there isnt more regulations and warnings if ozone is this dangerous as stated in many places.

Is the dangerous ozone levels set way too low or what?
Anyone know?

Belowzero - 3-7-2021 at 04:15

Quite often those limits are set very low, the chemical industry is one such example.
Also it is quite a different if this exposure is continous and permanent, quite different from incidental exposure with the proper precautions.
Smoke from burning wood is also quite unhealty, daily exposure to high concentrations will shorten your lifespan.
A couple whiffs every now and then is probably not measurable.

Fyndium - 3-7-2021 at 07:02

Occupational exposure is never comparable to occasional and rare exposure. Workforce can be exposed to the materials for 8-12 hours a day, 5-7 days a week around the year. Hence, even decimal ppm concentrations can cause exposure to quite significant amounts over the year, for every whiff you intake few nanograms or so, but over the year you easily get grams of it in your body.

This is why I first look LD50, LC50 and known carcinogenic and biopersistent aspects, because they give a much better idea how careful you have to be.

Also, looking into perspective, some time ago I realized I treated sodium cyanide as an ultra-dangerous superpoison that I used excessive safety gear, but then I once handled a powder in free room air without any protection that had three times lower LD50. It was considered toxic without lasting effects (unless fatal) and it did not have any major warning signs like NFPA blue 4, but the actual LD50 surprised me.

macckone - 3-7-2021 at 21:33

NO2, Chlorine, Chloroacetone, H2S, SO3, Ozone, Ketene, Benzene, Mercury Nitrate, Mercury Acetate, lots of other stuff.

I try to avoid Dioxin and PCBs and Neurotoxins like Organophosphates and organo-mercury compounds.

It all comes down to what you can safely deal with and how worried you are about long term exposure.

j_sum1 - 3-7-2021 at 22:02

Probably uranyl acetate is my most dangerous. But it is pretty tame sitting in its jar.

Mateo_swe - 4-7-2021 at 02:50

Lets say you want to do some reactions in your home lab that call for using one of the more high toxic compounds.
One can get one of these 3M 6800-type Full Face Respirator masks (or the Chinese copies) and attach different filters to them.
The filters are for different categories of chemicals like organic vapours, acid compounds, ammonia type compounds etc...
The Chinese copies are just about 40Euros, quite cheap for a life insurance.
But do these work good and is it safe if a accident happen and im wearing one of these?
Do any of you use such masks?