Sciencemadness Discussion Board

Knock out hazards 2.0

aromaticfanatic - 12-10-2020 at 20:47

I had asked this question a day ago or so but was told to just research what I'm doing. I do that already, however someone mentioned that I was making a valid point and it moved me to repost here. Here is what I said from the best of my memory:

What are some knock out hazards in the lab? There are obvious ones like chloroform (not like the movies though), ether, anything that can displace oxygen, and the like. However, I have also discovered some not so well known knock out hazards.

An obvious class of knock out agents are vasolidators. They cause a drop in blood pressure which leads to becoming unconscious. Isopropyl nitrite fumes have an immediate vasolidation effect. Nitroglycerine is a well known vasolidator. ETN is one as well but since its vapor pressure is much lower than nitroglycerine, there isn't much risk besides a headache after handling the plastic bare handed for a long time.

So you can already see a difference between the generic vasolidators. Some are much more potent than others and I don't think there is a scale that helps you figure out how strong of vasolidators they are. In a serious accident where, say, a lot of hot isopropyl nitrite is knocked out of the fume hood for some reason. The lab space is small and suddenly you have a large fire hazard. As you are cleaning things up you become very light headed and warm and soon you pass out. You are found dead in your lab the next day. It may sound exaggerated but it's a real possibility for some of us. Or the perfect experiment for something like this to happen could be during sodium azide synthesis. Hydrazine fumes, temps need monitoring, sodium azide is well known to be lethal, and the isopropyl nitrite (I have smelled the fumes while making the nitrite and it does cause an almost instant warm feeling but hasn't knocked me out before, but someone with an already low blood pressure or someone who stands up right after smelling it, may pass out) is a possibility to render you unconscious.

Some lesser known knock out agents are cyanide and azides. The sodium salts are both highly water soluble and have similar LD50s. I believe they both act to stop oxygen from being absorbed or transported in the blood stream. Sodium cyanide has a knock out effect and in a Reddit Q&A, CodysLab actually has mentioned passing out from cyanide even though he had the antidote and took it. Some was kicked up in the air and since it was a fine dust he inhaled quite a bit on accident. He administered sodium thiosulfate and mentioned he still passed out. This makes sense as the cyanide he inhaled quickly acted to stop hemoglobin from picking up any oxygen. No oxygen = brain ceases to function properly = unconscious.

Sodium azide's knock out effect is said to be much more potent than cyanide. It has very unpleasant effects at around 20mg and potential to knock you out in slightly larger doses.

These are scary things. While you would likely survive the less lethal knock out doses, you are in a lab around highly dangerous chemicals. When you are knocked out, you can't fight a fire, you can't wash chemicals from your eyes, you can't flee the lab from anything. This is obviously extremely dangerous.

The person who mentioned that my original post was a good idea to keep up and not delete also found out Xenon is an anesthetic and a definite knock out hazard (not just from displacing the air).

So there are obvious ones, and then there are not so obvious ones and even after a good amount of research, many people may miss that. I knew cyanide pretty well but I never realized the knock out potential it may have in less lethal amounts despite a good amount of research on the insidious chemical.

There are varying scales of severity as well.

So, having said that, are there any other knock out chemicals that are lesser known but may be found in amateur chemists' labs?

Sulaiman - 12-10-2020 at 21:54

A list would be too long to remember easily.

Better to research your starting chemicals and expected products and by-products on a case-by-case basis for each experiment.
You can simultaneously research handling, storing and disposal.

B(a)P - 13-10-2020 at 00:43

Quote: Originally posted by Sulaiman  
A list would be too long to remember easily.

Better to research your starting chemicals and expected products and by-products on a case-by-case basis for each experiment.
You can simultaneously research handling, storing and disposal.


I still think it is interesting to explore. Many aspects of chemistry are too long to remember, getting a consolidated list of this sort of thing is therefore useful I think.

Arsenic trioxide is one such chemical.

teodor - 13-10-2020 at 01:56

Quote: Originally posted by B(a)P  

Arsenic trioxide is one such chemical.


What is the knock-out effect of As2O3? Could you describe some case to make us better understand the danger?

B(a)P - 13-10-2020 at 02:32

Quote: Originally posted by teodor  
Quote: Originally posted by B(a)P  

Arsenic trioxide is one such chemical.


What is the knock-out effect of As2O3? Could you describe some case to make us better understand the danger?


Exposure to As2O3 is via inhalation of dust or dermal contact.
As2O3 causes tachycardia, reducing blood pressure and potentially leading to a loss of consciousness.

teodor - 13-10-2020 at 02:52

Quote: Originally posted by B(a)P  
.
Exposure to As2O3 is via inhalation of dust or dermal contact.


Most descriptions which says "inhalation of dust" I believe are referring to some factory conditions where the dust is everywhere and the whole day. I always puzzled how this rule could be applied to a case like opening a bottle and get few spatulas of the chemical or collecting scattered powder, so the condition we usually have in lab.

Fyndium - 13-10-2020 at 09:35

What are the go-to antidotes for cyanide poisoning and are they available otc?

njl - 13-10-2020 at 09:40

An organic nitrite, vitamin b, and sodium thiosulfate if I recall correctly. All of which are OTC.

itsallgoodjames - 13-10-2020 at 09:41

Quote: Originally posted by Fyndium  
What are the go-to antidotes for cyanide poisoning and are they available otc?


According to Wikipedia:

The United States standard cyanide antidote kit first uses a small inhaled dose of amyl nitrite, followed by intravenous sodium nitrite, followed by intravenous sodium thiosulfate

aromaticfanatic - 13-10-2020 at 11:04

Quote: Originally posted by Sulaiman  
A list would be too long to remember easily.

Better to research your starting chemicals and expected products and by-products on a case-by-case basis for each experiment.
You can simultaneously research handling, storing and disposal.


You don't need to memorize a list, you can write it down and scan the list for the chemical you are researching as a pre check. Many don't know about cyanide's or azide's knock out potential, they just know at around 200mg both will kill a grown man. But, the extremely rapid action of them as well as the knock out effect at lower doses are often overlooked in chemistry, especially the azides.

paulll - 13-10-2020 at 11:54

This would be on my mind if I was doing anything that might release Hydrogen Sulfide.

Deathunter88 - 13-10-2020 at 20:04

I think for most of the "knock out" hazards you mention you're really referring to "you're dead" hazards. There are very few compounds we work with which knock you out fast without causing significant permanent damage so I don't really thing the list would be too useful.

OldNubbins - 14-10-2020 at 09:10

A list might be an interesting novelty but in no way, shape, or form should be referred to as a matter of safety. If a substance has the capability to 'knock out' a person with little or no warning, brain damage has probably already occurred and will likely continue as the victim lies unconscious. To me, that seems like more poor preparations and faulty procedures used rather than the substance's inherit dangers. Lists can lead to insufficient information and complacency. Maybe it's a good starting point if your goal is to knock yourself or someone else out, but a better overall understanding of the process and all chemicals involved is more responsible.

'Knock out' potential just seems oddly specific, since there are so many other ways chemicals can incapacitate or kill you.

teodor - 14-10-2020 at 09:31

I personally think such a list is very important.

If you will try to use ANY published value of danger, you never can discover that you should be more careful, let say, with HCN than with HBr, because the HCN has IDLH 50 ppm and HBr has 30 ppm.

[Edited on 14-10-2020 by teodor]

Fyndium - 14-10-2020 at 10:18

I thought very long ago how one could make an ex tempore setup for working with extremely toxic stuff. The idea was to make a tent, which is on negative pressure, and lead a tube with air pump into full body suit, including face, to generate overpressure so any leaks will go outwards.

Just as a thought, but if I'd had the space and need/want to work with something that I consider too dangerous, it doesn't sound too impossible to do.

zed - 18-10-2020 at 04:14

https://www.sciencemadness.org/whisper/viewthread.php?tid=15...

Fyndium. Positive pressure protection, is something I know a fair amount about.

I just posted on the matter, a few minutes ago. You have the link.

[Edited on 18-10-2020 by zed]

[Edited on 18-10-2020 by zed]