Hidden Poison

[SLAG]

Mr. Frosty is correct. The lowest threshold for the detection of phosgene is 0.4 parts per million. That number is four times the toxic level for phosgene in air. Many people do not even smell the gas at that level. Phosgene's odor is an unreliable test. Many people need a higher level to discern the gas. So the sniff test is no help. Incidentally it smells like freshly mown hay or green corn.  The symptoms of phosgene poisoning are slow to develop & detect, they are most often missed entirely. Many folks who spot tested for chloromethane refrigerant leaks, got severely poisoned before they realized it, if at all.

At the risk of repetition, allow me to gather up the information, plus additional facts in one post. Phosgene is also known by name of carbonyl dichloride, or carbonic chloride. It is  a gas. It is not flammable & it readily breaks down in water. It was first synthesized in 1812 by a John Davy. (not Sir Humphry Davy).The gas was first used by the Germans in the First World War. It accounted for 85% of the 100,000 poison deaths experienced during that conflict. .

The chemical is used for many processes like making plastics (e.g. polycarbonates), pharmaceuticals, chemical feed stocks, and numerous other uses & products. A blacksmith and other metal workers can encounter phosgene in many ways. Some of those ways are by heating any chlorinated degreaser that is used to treat metal. Also brake fluid will give off phosgene, when heated.  Subjecting  polychlorinated solvents to the sun or ultraviolet rays generating from arc welding will give off phosgene . Likewise paint removers should not be kept close to a heat source. W.D. 40 penetrating oil should not be heated. If any such chemicals need a heat treatment. Do so in a well ventilated outdoor spot and stand upwind. A fan, placed upwind would be a nice additional touch, but probably not necessary. The use of an activated charcoal containing respirator would be an additional precaution. Freon will produce phosgene if heated. Heated fire extinguisher chemicals can give off that gas. E.g. Halon , etc. A lit cigarette can start the reaction, as well as the heat of the fire being extinguished.

So, how do we guard against phosgene gas? Place all solvents especially degreasers well away form a heat source. wash all suspect iron with a non chlorinated solvent, do so in a well ventilated spot and keep all chemicals away from an arc welder. Their containers would be better off being covered  in a black colored "shroud". (like two layers of black plastic garbage bag).

I hope that this post is both informative and useful.   Cheers     SLAG.

Edited April 14, 2016 by SLAG
editing for clarity

[Frosty]

Robert: I certainly HOPE talking about how lucky I've been doesn't give anybody the idea luck is a valid precaution!

My sole intent was to say how lucky I am to be alive in spite of the risks everybody ran. Luck should NEVER be part of a safety program! Luck can go either way.

The can of brake cleaner left my shop for good yesterday about 3:00pm. right after Judge Judy. I'll be doing a label by label "vetting" of everything in there. 

Frosty The Lucky.

[SLAG]

Phosgene Detection,

Modern phosgene detectors are electronic, I assume that they are prohibitively expensive. (some one please correct me, if that is not so). The old test was potentially hazardous. Many people got poisoned by using it. The detection method was a flame test. Essentially, a small gas torch was used. It burned a gas such as propane, butane, propylene, etc. The torch had a sniffer tube plus a copper reaction plate in the flame nozzle. The air would be sucked into the flame and the flame would turn bright green if there was any phosgene in the air.

Regards all.    SLAG.

[BeaverNZ]

I am a welder by trade and have been doing for longer than I like to think,I used to use alot of CRC Brakeclean for degreasing aluminum for Tig welding till I realised that it breaks down with ultaviolet light even the stuff that has evaporated into the atmosphere of your workshop so please dont use this when welding is nearby. I now use Wurth brakeclean which is some type of alcohol which is safe. These brands may not apply except in Australia and new Zealand Cheers

[Anachronist58]

Mr Frosty, in case you are addressing THIS Robert, I was not thinking of you as I was posting, I was emphasizing my lack of qualification as concerns this very important subject.

I too, am an extremely lucky (spelled fortunate) guy, as evidenced by the permanent '55 Chevy doorframe-shaped crease in the top of my skull, and several broken vertebrae.

I am quite sure that I have already exceeded my lifetime quota of <luck> so I tend to <try> to be obsessively cautious. Stop laughing, Mrs Taylor

I too enjoy a good play on words.

Robert Taylor

[Charles R. Stevens]

It was my understanding that chlorinated brake cleaners were replaced in industrial and automotive applications back in the late 80's. Right along with CFC refrigerants in automotive applications. 

But this could be the faulty memory of an old automotive tech. 

[Frosty]

Okay, I was concerned I'd maybe given folk the wrong impression, this is too important to get wrong. It Is a good place for the tendency of folk who don't really know a subject to be over cautious.

You keep saying, "Mr. Frosty," am I in trouble. . . again? More trouble than usual that is? 

I have matching D-6 dozer instrument panel dents in my shins from the one time I got overconfident and didn't check to make sure the seat belt is latched properly. I mean heck flat ground, meadow, just rolling up the organic mat and shoving it off the hill. What's to go wrong? Find a pickup truck sized granite glacial erratic boulder? Oh come ON what are the odds of that?

I remember the tracks slamming back into the ground before the pain whited out my universe. A friend of mine, Bob said I didn't move or say a word for a good 15 minutes then just started cussing. I got it into neutral though, some instincts don't need a functioning fore brain I guess.

A few more incidences and I'm not counting on luck for nothing, I don't even play cribbage for points anymore.

Frosty The Lucky.

[Charles R. Stevens]

Jerry, my luck tends to be so bad, it gets me in deap and won't let me die...

[Frosty]

9 minutes ago, Charles R. Stevens said:

Jerry, my luck tends to be so bad, it gets me in deap and won't let me die...

Charles: Bad luck makes you think ahead, it's being smart that keep you alive.

Frosty The Lucky.

[Anachronist58]

Those pesky erratics! May I call you Jerry? I tend often to be possessed of an overly formal affect. I once parked a hewing hatchet in my shin, but I still think you have me beat with the D6.

Robert

[AnBello]

Just a quick question. SLAG mentions that many substances, including the famous WD40, can give off phosgene. A couple of days ago I was reading a post about forge welding, particularly canned damascus, with some WD40 to absorb the oxygen, but it also included people talking about using it for normal forge welding ("it will protect the piece from oxygen in the low temps, until borax melts and takes over" sort of). I don't remember the thread now.

I just wanted to ask a bit about this, because of the different voices. Is it very dangerous and shouldn't be done, or is it a risk that can be controlled with some precautions? (ventilation, staying away)

[JHCC]

9 hours ago, Andres Bello said:

Just a quick question. SLAG mentions that many substances, including the famous WD40, can give off phosgene. A couple of days ago I was reading a post about forge welding, particularly canned damascus, with some WD40 to absorb the oxygen, but it also included people talking about using it for normal forge welding ("it will protect the piece from oxygen in the low temps, until borax melts and takes over" sort of). I don't remember the thread now.

I just wanted to ask a bit about this, because of the different voices. Is it very dangerous and shouldn't be done, or is it a risk that can be controlled with some precautions? (ventilation, staying away)

I was just about to ask the very same thing.

[Charles R. Stevens]

I think "being smart" or in my case too dang smart may be part of the probblem, lol

[Anachronist58]

SLAG, or anyone else - Do we have a valid Citation in reference to WD-40 as a phosgene hazard? I just read through the MSDS, and have found no such indication of said hazard.

Is this a real hazard or an urban legend?

WD-40 Brand Spot Shot Instant Carpet Stain Remover, on the other hand, is Very Nasty, and is listed as a <trace> phosgene hazard.

I think it is very important that we get the definitive dope on this.

Robert Taylor

[Frosty]

16 hours ago, Anachronist58 said:

Those pesky erratics! May I call you Jerry? I tend often to be possessed of an overly formal affect. I once parked a hewing hatchet in my shin, but I still think you have me beat with the D6.

Robert

Certainly you may call me Jerry, thank you for asking. Yeah, you just never know when you'll stumble across an erratic. Slamming into it with the rented D6 made no visible impact on it, I don't think it jiggled a smidge, no visible effect at all. It's still sitting happy as the day the glacier dropped it where it came to rest. Deb dubbed it "goat rock" even though there is a buttress on a Mtn. peak too our east with that moniker.

I learned my lesson though, don't argue with BIG rock unless sufficient explosives are involved and go along with what Deb wants to name things. I have better pics of the thing but no idea where.

Frosty The Lucky.

[Dogsoldat]

Well that might explain it...   I do remember reading someplace about the wobble in the earths rotation changing.  And you do have better leverage up there Frosty 

 

[Frosty]

8 minutes ago, Dogsoldat said:

Well that might explain it...   I do remember reading someplace about the wobble in the earths rotation changing.  And you do have better leverage up there Frosty 

 

You surprise me again, I was expecting a bunch of old goat jokes.

Frosty The Lucky.

[JHCC]

Just now, Frosty said:

You surprise me again, I was expecting a bunch of old goat jokes.

Frosty The Lucky.

I couldn't think of any good ones. Now I feel sheepish.

[Frosty]

I feel fleeced.

Frosty The Lucky.

[Daswulf]

Frosty, I think your goat ate a couple bowling balls. 

[Frosty]

Not pregnant either, African Pygmys are supposed to look like kegs on legs.

Frosty The Lucky.

[Charles R. Stevens]

Lol, bad puns aside I have sheep practice multiplication as I type. #3 has a pair on the ground and #6 has one on the droid and working on a second. 

Jerry, if that working cesium or is it a pair of goatlings in the incubater?

Well that answers that question. 

[Charlotte]

Had a neighbor that was an electrical contractor.  Nice Guy!  But, I had a hard time convincing him to burn wire recovered for job sites.  I finally convinced him when I pointed out that the chlorinated crap vapors were headed to this wife and two babies.

Little latter own the scrap yards started refusing burned wire because of the Law.   Just to point out that most plastics used in Industrial settings have chlorine in the molecule and are dangerous when heated, melted or burned.   

 

[SLAG]

Anachronist58, 

After reading your post I got back to my sources & did not find it again. (so WD40 is off the hook as far as phosgene generation is concerned). Never the less WD40 is a trade secret mixture, so the exact components are not specifically known. (also the company has altered its components from time to time and even for different countries, & could it be changed without notice in the future.).  But there is NO chlorine to speak of.

The company decided to keep the technology as a trade secret instead of disclosing the ingredients in a patent specification. It was vaguely disclosed that it has (in a material safety data sheet, M.D.T.S.) & that it is a mixture of 50% aliphatic hydrocarbons, under 25% petroleum base oil, propellant such as butane etc. which has been changed to carbon dioxide & ?% mystery other. Try https://web.archive.org/web/20140119014037/http://www.wired.com/science/discoveries/magazine/17-05/st_whatsinside if you want some of the specific constituents, of the above mentioned chemical categories. A German formulation is somewhat different.

It is strongly suggested that the product be used but not be burned off when it's disposed    SLAG..

Edited April 16, 2016 by SLAG
added clarity

[Charlotte]

4 hours ago, Charlotte said:

Had a neighbor that was an electrical contractor.  Nice Guy!  But, I had a hard time convincing him to burn wire recovered for job sites.  I finally convinced him when I pointed out that the chlorinated crap vapors were headed to this wife and two babies.

Little latter own the scrap yards started refusing burned wire because of the Law.   Just to point out that most plastics used in Industrial settings have chlorine in the molecule and are dangerous when heated, melted or burned.   

 

Should have read not to burn wire.