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Topic: Methanol poisoning (inhaling)  (Read 26706 times)

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Offline FelixA

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Methanol poisoning (inhaling)
« on: May 01, 2014, 07:20:32 PM »
I'm not a chemist, but I feel that this might be a good place to ask this question:

I keep a full (unopened) bottle of windshield washer fluid in my trunk for reserve, as many people probably do. The fluid contains methanol (methyl alcohol), about 30% of the total weight. Methanol is highly toxic if swallowed or inhaled.

Just recently it was a warm spring day with sun shining all day. The interior of the car and the trunk must have gotten really hot. When I got home from work (at night, it was a lot cooler then), I opened the trunk to find a puddle of blue liquid in there – the cap of the washer fluid bottle had somehow popped open, but there was still a protecting seal that had remained in place. The seal does not let any liquid out, so it was a mystery how this puddle had formed inside the trunk.

I suspect that the explanation is in the boiling point of methanol being fairly low (about 150 degrees) and even with it not boiling, it still vaporizes at a fast rate when it gets hot. So apparently methanol started to vaporize inside the bottle and found its way out through a tiny leak in the seal. This has probably happened over the course of several hours. I estimate that about 10 oz of the contents of the bottle got out. If most of it is methanol, it’s a lethal dose if inhaled in a small compartment such as the trunk, or the entire car.

10 oz of methanol weighs a little over 200 grams. The trunk has volume of about 1 cubic meter. The concentration would thus be 200g/m^3. This is a) highly flammable, b) highly toxic – a couple of breaths and you are severely poisoned (the threshold level for immediate life threatening danger is a concentrate of about 10g/m^3).

Anyone else find this a bit worrying? Or is my reasoning really wrong here? Even though I did not directly breathe in the fumes in the trunk, I still drove the car for a couple of hours, and the fumes are likely to spread inside the cabin as well. Also, methanol odor is very weak at low concentrations, so even if you don’t smell it, breathing it in over a long period of time can have serious long term effects.


Offline Archer

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Re: Methanol poisoning (inhaling)
« Reply #1 on: May 02, 2014, 03:01:54 AM »
 First of all if 200g escaped then at 30% this is only 60 grams.

Secondly at 30% aqueous solution methanol does not evaporate as quickly.

As soon as the truck was opened the air entering it would have diluted it very quickly.

If you are very worried or you are feeling unwell then go to a hospital.

The standard treatment for acute methanol poisoning is administration of ethanol to saturated the enzymes in your liver which convert relatively harmless methanol into formaldehyde which is toxic.
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Offline Borek

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Re: Methanol poisoning (inhaling)
« Reply #2 on: May 02, 2014, 03:54:12 AM »
If the methanol run out by evaporation, it had no chance to condense back to create the blue puddle.

And if the concentration in air were high enough to be dangerous, you would already feel effects - at least some headache, weakness, this kind of things.

Cars are not airtight, and the air inside is exchanged quite fast, so the highest possible concentration is much lower than the one you tried to estimate.
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Offline Archer

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Re: Methanol poisoning (inhaling)
« Reply #3 on: May 02, 2014, 04:07:08 AM »
If the methanol run out by evaporation, it had no chance to condense back to create the blue puddle.

I misread the original post, I thought that the bottle had leaked from the pressure.
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Offline curiouscat

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Re: Methanol poisoning (inhaling)
« Reply #4 on: May 02, 2014, 04:14:37 AM »
Besides your estimation procedure seems flawed. The gas phase gm/m3 is what's relevant. You need to apply a Henry's Law / VLE type of step to go from Liq. to gas at that temp.

Offline FelixA

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Re: Methanol poisoning (inhaling)
« Reply #5 on: May 02, 2014, 07:33:14 AM »
I was wondering about the puddle formation...perhaps there must have been a leak with actual liquid pouring out then. The strange thing is, now when I examine the bottle, even turn it upside down, nothing leaks out (the seal prevents it). Perhaps the temperature change can affect it?

How dangerous is skin exposure? When I noticed the puddle in the trunk, my first instinct was to clean it without thinking too much about the dangers of methanol. After all, it's "just" washer fluid. So I moved the bottle, which was wet, out of the trunk and brought it inside for cleaning. I placed paper towels on top of the puddle to dry it. I did all this without wearing any gloves. Like I said, when you have washer fluid spill in your trunk, the first instinct is to clean it up quickly. Honestly, I didn't even think about methanol at that point. Am I really dumb? Is this worthy of a Darwin award?



Offline Archer

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Re: Methanol poisoning (inhaling)
« Reply #6 on: May 02, 2014, 09:40:22 AM »

I was wondering about the puddle formation...perhaps there must have been a leak with actual liquid pouring out then. The strange thing is, now when I examine the bottle, even turn it upside down, nothing leaks out (the seal prevents it). Perhaps the temperature change can affect it?

How dangerous is skin exposure? When I noticed the puddle in the trunk, my first instinct was to clean it without thinking too much about the dangers of methanol. After all, it's "just" washer fluid. So I moved the bottle, which was wet, out of the trunk and brought it inside for cleaning. I placed paper towels on top of the puddle to dry it. I did all this without wearing any gloves. Like I said, when you have washer fluid spill in your trunk, the first instinct is to clean it up quickly. Honestly, I didn't even think about methanol at that point. Am I really dumb? Is this worthy of a Darwin award?


I don't think you have too much to worry about.

In order for acute poisioning to happen you have to ingest quite a considerable quantitiy.

I have had it on my hands loads of times (once it had got through a small hole in my latex glove and my hand was bathing in it for about an hour), I once saw someone squirt it in their eye (no lab specs) and I often use my nose to see if all of the solvent is removed from my product.

I am still here and have 20:20 vision. Mind you I think my blood alcohol is always above 20 mg /100 ml (or 0.02% if you are in the USA) so my alcohol and aldehyde dehydrogenase have no time to metabolise the methanol and my kidneys get rid of it unchanged.

Seriously though, any chemical can be bad for you, methanol is really only going to cause huge problems if you ingest a large quantity.

Quote
Humans - Ingestion of 80 to 150 mL of methanol is usually methanol is usually fatal to humans (HSDB 1994).  One worker died from exposure to vapor ranging from 4000 to 13,000 ppm over 12 hours (ACGIH 1991).
The concentration of 4000 ppm is roughly equivalent to a total of 1140 mg/kg over the 12 hour period (see end note 2).

Poisoning by nonlethal doses can be described in three stages:
(1) narcotic stage similar to ethanol;
(2) latent period of 10-15 hours;
(3)  visual disturbances and central nervous system lesions (Rowe and McCollister 1981).  Visual disturbances can lead to blindness due to edema of the retina and atrophy of the optic nerve head(HSDB 1994). 

Third-stage CNS lesions include headache, dizziness, abdominal, back, and leg pain, delirium that can lead to coma, and nausea (HSDB 1994).  Formic acid production causes severe metabolic acidosis (Rowe and McCollister 1981).

http://www.epa.gov/chemfact/s_methan.txt
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Online Babcock_Hall

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Re: Methanol poisoning (inhaling)
« Reply #7 on: May 02, 2014, 11:37:10 AM »
There are alternatives to ethanol as an antidote.  Fomepizol (4-methylpyrazole) is one.

Offline Archer

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Re: Methanol poisoning (inhaling)
« Reply #8 on: May 02, 2014, 12:09:23 PM »
There are alternatives to ethanol as an antidote.  Fomepizol (4-methylpyrazole) is one.

my way is better,  especially if it's a single malt from Isla :)  it comes with it's own ADH1 inhibitors
 
http://www.ncbi.nlm.nih.gov/pubmed/19013301
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Offline 408

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Re: Methanol poisoning (inhaling)
« Reply #9 on: May 02, 2014, 01:41:04 PM »
You are fine.

But a couple drinks would not hurt, as Archer suggests. 

Offline Archer

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Re: Methanol poisoning (inhaling)
« Reply #10 on: May 02, 2014, 02:23:56 PM »
Just a couple mind you, you dont want to over do it and make a fool of yourself.

 One pint of beer should saturate your liver, the second maintains saturation as if it drops below 0.02% you are no longer eliminating at zero order kinetics, it becomes something resembling Michaelis Menton kinetics. The second also washes the methanol out.

Please seek medical advice from a qualified practitioner if you are at all concerned. Although as 408 says you'll be fine.
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Offline FelixA

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Re: Methanol poisoning (inhaling)
« Reply #11 on: May 02, 2014, 04:11:52 PM »
Just a couple mind you, you dont want to over do it and make a fool of yourself.

The incident happened 4 days ago. Would consuming alcohol still help? I thought the methanol should be processed by now?

Please seek medical advice from a qualified practitioner if you are at all concerned. Although as 408 says you'll be fine.

To be honest, I'm starting to be terrified (and I guess paranoid too). After the incident, I was like nothing had happened. Only two days later I started reading about methanol online, and that's when I started panicking.

There is something I don't understand...millions of people buy windshield washer fluid every year, and surely, a good percentage of them will spill it in their trunk, on themselves, etc. Yet, how many of those seek medical advice? What would they even do if I have no clear symptoms? Or can symptoms develop only weeks later?

Offline 408

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Re: Methanol poisoning (inhaling)
« Reply #12 on: May 02, 2014, 04:21:12 PM »
It has been 4 days.  You are in the clear.  Methanol poisoning shows up faster.  You would have noticed an initial intoxication similar to ethanol, followed by a second more severe set of symptoms (vision loss, etc) within a day or two.

But as this time has passed, you are 100% fine.  But Dr. 408 recommends a good dose of ethanol simply for your nerves. 

Offline Borek

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Re: Methanol poisoning (inhaling)
« Reply #13 on: May 02, 2014, 04:26:58 PM »
If it was four days ago... I think you should make yourself a drink, or open a beer, or whatever you find calming. Not that it will change anything, your organism already got rid of all the methanol, but it will help you relax and stop worrying about nonexistent problem ;)

Seriously, if you had no immediate symptoms, and you have no symptoms now, nothing worse can happen. This is not some kind of delayed effect that takes weeks to develop, it is quite fast - problems start hours after exposition. Wikipedia says up to 30 hours, I recall being told up to one day (24 hours). That means if anything, problems should have started three days ago. They didn't.

Edit: 408 posted exactly the same while I was composing my message - but I am leaving what I wrote, just to show he is not the only person thinking this way.
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Offline Corribus

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Re: Methanol poisoning (inhaling)
« Reply #14 on: May 02, 2014, 04:53:41 PM »
Think of it this way - if a substance was so dangerous that spilling about a cup of it could easily kill you, do you think they'd really be putting it wiper fluid?

In my graduate days we used to squirt that crap everywhere.* Friday afternoon group meetings were more dangerous to my health. :D

*Of course, people used to play around with mercury, too, so I guess that's not necessarily a good argument.
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

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