Phosgene Gas

[dixie2005]

I find that I'm often exposed to phosgene gas when welding. There's usually residual gas in pipes when I'm servicing equipment that produces phosgene when heated. I'm wondering if anyone has any advice for me to help deal with this unpleasant and potentially harmful event? Do any of you guys use a mask?

Thanks!

[joeywpittman]

recover the refrigerant longer (pull a vacuum on the system)

[phosgene]

I'm hurt. You don't like Phosgene.

You could also try running some nitrogen through the line.

[derrick1623]

i only get exposed to phosgene when brazing, i guess i'm lucky.

nah, seriously, evacuate longer before exposing yourself to the situation, and "try" to keep your health.(be careful otherwise)

[chillrdude]

Dixie, I would suggest changing your evacuation habits. I lost a buddy of mine about 15 years ago to phosgene gas poisoning, he got in a hurry, breathed a bunch of it, walked around for a week feeling terrible, doc told him it was the flu. His wife found him dead on the kitchen floor the next morning. 27 years old with a wife, a 3 year old and one on the way, wife lost the baby a few weeks later. Something to think about.

[acjourneyman]

If you have a good reclaim unit and do a double evac you should never have to worry about phosgene,I have welded on some pretty big lines and have not been exposed, the only time I ever have been is when I cut corners.

[dixie2005]

Allright guys, thanks for the replies. I'm going to sharpen up my procedures!

Thanks!

[john dalton]

Good Afternoon Gentlemen,

Phosgene, we like you, we just can’t stand the smell of you, that’s all.

Most of us already know that phosgene gas is a byproduct of some refrigerants when they are exposed to an open flame, or extreme heat. We also know that this byproduct is extremely dangerous, even in small trace amounts. Since we cannot remove the open flame, or extreme heat needed to braze our systems, we need to do the next best thing, remove the potential of these refrigerants from reaching the open flame, or extreme heat.

This isn’t always entirely possible based on the fact that small amounts of trapped refrigerant can linger in small amounts of refrigeration oil that is pooled inside our refrigeration circuit. But as already been pointed out, good refrigerant recovery procedures and practices can reduce our potential of coming into contact with this extremely dangerous byproduct.

Good and sound recovery practices, its good for the environment, and good for us as well.

Respectfully Submitted,
John J. Dalton

[rubobornot]

I read an article that said that phosgene gas could be a factor in Legionnaire's disease [url]http://www.pmengineer.com

[270wsm]

I read an article on Phosgene gas that says the only refrigerant that creates "true" Phosgene gas is R-12. The gas produced by R-22 is similar and Harmful, but is not really phosgene. Im just quoting this, not sure how true it is.

[270wsm]

Being extremely toxic in small amounts, phosgene formation was a real concern when traditional refrigerants (R11, R- 12, R- 113, R- 114) decomposed. Phosgene contains two chlorine atoms and an oxygen atom. It will only form when oxygen is present and only the refrigerants with chlorine attached will produce phosgene (not HFCs). R22 has only one chlorine atom per molecule, so it is extremely difficult, chemically speaking, to get another one attached to form phosgene. Decomposition of R-22 or HFCs may form other carbonyl fluorides, however they are not as toxic as phosgene.

http://www.refrigerants.com/msds.htm

[mattm]

I started out in this trade repairing through the wall units way before recovery. We would blow the charge and un-sweat the compresor. 9 times out of 10 you would get a face full of phosgene and gag the hell out of ya. Normal hazzard of the job then with a cancer stick in my mouth. If I only knew then what I know now........

[ruud-man]

Back in the days when I would be in an R-12 enriched atmosphere and casually draw on my cigarette.

Drawing refrigerant across a glowing ember of tobacco.

Smoooooooth.

[flange]

i am blessed (read that cursed) with the inability to smell phosegene. in addition i cannot smell acid when a burnout has occured. for this reason i have to do things a little more precisely than some others weho may "cheat" from time to time.

[Condorsouth]

I find that I'm often exposed to phosgene gas when welding. There's usually residual gas in pipes when I'm servicing equipment that produces phosgene when heated. I'm wondering if anyone has any advice for me to help deal with this unpleasant and potentially harmful event? Do any of you guys use a mask?

Thanks!

It only requires 1 part phosegene gas in 600,000,000 (million) parts (air you breathe) to kill a human being. You must have a guardian angel. Short of a self-contained breathing apparatus (SCBA) such as those use by hazmat and firefighters teams I don't think a mask would do much good. EPA told you all of this stuff when you were certified. Get your book out and re-read it. I can't get the straight of it but I have heard that only R-12 will convert to phosgene under high temperature. If R-12 will then I would think that R-22 and maybe some of the others would. Maybe it is just the R134a that will not convert to phosgene under high temperature. Why take a chance...this is not a dress rehersal!!!

OOPS!!! I should have read all those smart guys down below before posting.

[freonguy]

There are several great replies on ' phosgene ' in this thread, and depending on the refrigerant, it may or may not be phosgene; that being said, any of the refrigerants broken down with heat make nasty chemical compounds you don't want anywhere near your lungs.

As for the information about evacuation protocol, all are valid points. Where I have been ' burned ' so to speak in the past was when you were in an area and had to braze where refrigerant had leaked and due to the fact it is heavier than air, had pooled, specifically supermarket refrigerated cases.

A fan would help, but the best thing I found was to plug in the shop vac, stick the hose in the case ( making sure the exhaust was pointed away ) let it run for a few minutes. Viola!, the refrigerant had been ' evacuated ' from the case itself.

Every situation is different though. I used to do a fair bit of work in refrigerated holds of salmon troll boats. SCBA was the only way when there was a leak.

Just my 2 cents;

Dave Beauchesne CM
aka: Freonguy

[hvacker]

When, in the military, I was given training in Chemical warfare. It was said phosgene had a sweet, not unpleasant odor.
So, what are you smelling? Freon's decompose at high temperatures and form hydrofluoric acid and if the compound contains chlorine, hydrochloric acid. These are impossible to breathe. If water or oxygen are present, smaller amounts of phosgene might be formed but the acids are the canary. So burning these refrigerants doesn't always mean you've produced phosgene, it also doesn't mean you haven't. You wouldn't be able to smell it with the other gases present.

[amickracing]

I've had problems with that before too, once it was plain scary. Don't remember leaving the site, calling a coworker asking him to go over and finish, or anything. Next thing I know I wake up in my bed feeling like I've been walked on by a horse and really unsure wtf just happened.

I doubt I was close to dying, but that was close enough for me!

If I have a problem similar to that I'll evac it down as low as my recovery machine will go, then I'll throw the vac pump on it for a while too since it'll pull harder.

No matter what though, be safe!

[hvacker]

The closest I've been to freon killing me was at a hotel in Wisconsin.
I was 3 stories down from the roof with a filter/drier apart. What I didn't know was the crew had begun to blow down the unit with r11. The r11, being heavier than air began to fill the mechanical room.
Somehow I realized I needed to get out. Like running out of oxygen a person looses ability to reason. Any way, I didn't feel my feet walking but I made it to fresh air and in about 5 min felt fine.
If I had passed out the crew wouldn't have come to the mechanical room for about another 1 1/2 hours.
Guess it wasn't my time.

[Allen]

I have attached two articles that are contained in one folder about phosgene gas. The long and short of the articles are that it very doubtful that phosgene gas is form from burning refrigerant. The articles says it this way highly unlikely.
There is another way that you can be sure that it was not phosgene gas you were smelling, you are living to read and write about it. Proper personal protective equipment for working around phosgene gas is a air line powered hood.
I have smelled that nose and throat burning odor produced when a torch flame burns some refrigerant, it is nasty but not phosgene.
Let the flames begin.
Allen