stainless steel - what are the exposure risks when working it?

[j-becker]

My material science engineering lectures are a while back I have to admit. So take the following as based on a basic understanding of metallurgy and chemistry: I am well aware that hexavalent chromium is nothing to ignore (while lesser oxidation states or elemental chromium is mostly harmless), however, chromium is typically substituting iron atoms and are thereby not even close to a hexavalent state in steel. It seems to me that you need rather extreme conditions (or or the presence of other elements/ compounds) to get it into that state. A welding arc (or EDM or to a lesser degree grinding) is a good candidate and welding fumes can therefore contain many nasty things including some hexavelant chromium. And as long as there is elemental iron or iron oxide is around, it would tend to prevent any hexavalent chromium from forming (but not CR(3+)). In my shop (lathe/mill) I usually aim for straw blonde chips so from my basic understanding I don't think that hexavalent chromium is on the list of things I have to worry about.

Try ro find some scientificially-based recommendations on the subject if you are worried. I would look for Europe/ Germany / the nordic countries and see whether they have picked up the topic for work exposure recommendations. These regulations normally cite the scientific basis and may be a better route to explore the subject than a google search.

 

[j-becker]

BTW, your skin irritation may not be due to the chrome but rather the nickel, another common ingredient in stainless. At least that is the usual suspect.

 

[RaisedByWolves]

That's a little harsh.

The whole point of asking here was to get a rational perspective.
There are plenty of authoritative sources of the real risk of grinding dust from stainless steel. My level of exposure is small enough that I seriously doubt it's an issue - but it's worth asking.

Your knowledge and experience leads to "you don't need anything beyond what you would typically use for procedures and PPE"

The consensus in the responses so far seems to be don't sweat it.

Thanks.

As a kid, I had access to mercury which I played with a lot. Also melted and cast quite a bit of lead (100's of pounds) in a closed basement. In general messed around with whatever was available. I also smoked for 10 years. A couple of years ago, a clean up project had me going through 3 gallons of acetone. I did it outside but never got gloves that it wouldn't eat through (rather quickly. Despite all logic, I rarely wear a helmet when I ride trails on my bike....

I try not to do stupid things, sometimes I succeed.

I have to admit his reply gave me a bit of a good natured chuckle.

I too played with mercury (Its mostly harmless) and smelted lead on my parents stove when they weren't home at 10yrs old. I held lead pellets in my mouth when we were shooting rodents and closed split shot with my teeth and still do.

Anyone who knows me on a personal level that hears this pretty much probably thinks to themselves "So that's why he XXX" or whatever, but I keep them laughing with my antics.

Fun fact, no one gets out of life alive.

Ive worked with hazardous substances my whole life and my own Vices are what worry me most.

 

[BGHansen]

This has been a good topic to broach (wait, can that lead to . . .). My dad was a high school shop teacher. He stopped over to my shop once while I was spot welding some sheet metal. My shop wasn't heated at the time, so I bought galvanized stock to avoid rust. I hadn't thought about galvanized being zinc-dipped steel. Just merrily spot welded away with white gas (zinc oxide) emitting from the welds and a white powder residue. My dad clued me into cleaning the zinc off before hand so I wasn't breathing it in. Could it lead to permanent damage? Don't know and don't worry about it because I don't expose myself to zinc oxide gas while welding anymore.

I was still working at General Motors during Covid and had to wear a mask at work. It took me a while to get used to it; I had trouble getting enough air for a few weeks. However, it was a blessing when I had to string some wire in the attic of the shop. It's insulated with fiberglass batts; in the past I'd start out with a mask, but would fog up my glasses and had trouble breathing; off came the mask. I'd come out of the attic coughing for a half-hour from the stuff I was breathing up there. Once I got acclimated to wearing a mask during Covid, the proper PPE was a Godsend after stringing some circuits. After crawling around with a mask for an hour, I pulled it once I hit the floor and had no hint of coughing.

One last war story, around 25 years ago I was cutting some sheet metal on a bandsaw and got a sliver in my thumb. No big deal, I dug it out with my jackknife. I was under our backhoe later that day doing whatever; got really filthy. A couple of days later I had a 104 F temp and a red line running up my arm; a bad infection and blood poisoning. I ended up in the hospital on IV antibiotics for a couple of days and a week more of twice a day IV's. Ever since, it seems like I'm much more susceptible to infections. So, I'm pretty diligent about washing out the cuts, slivers, etc. and covering them with Neosporin and a Band-Aid.

Well, I was cutting down a nasty Thornapple bush from our side yard and got a thorn poke in a finger. I dug it out with a lance, then did the normal wash my hands, soak in the hottest water I could take with Epsom salt, peroxide, alcohol, then Neosporin and a Band-Aid; all around 2:00 on 3/26, this past Tuesday. By dinnertime, I could tell it was going south. The finger with the "pokey" and the ones on either side were swollen, and the swelling was half-way down my palm. I spent a nice evening in the emergency room getting X-ray'd, doc doing an obligatory clean out, and a prescription for an oral anti-biotic. The finger has just a little swelling now, things are going in the right direction. Was the trip to the ER necessary? Maybe my body's immune system would have overcome the infection without the oral anti-biotic?

I guess the moral to the story is "If you're concerned about something causing you some harm, by all means take the appropriate measures to make yourself comfortable". In my case, I'm glad I went to the ER as I've have been stewing about my hand all night.

Bruce

 

[7milesup]

I dug it out with a lance, then did the normal wash my hands, soak in the hottest water I could take with Epsom salt, peroxide, alcohol, then Neosporin and a Band-Aid; all around 2:00 on 3/26, this past Tuesday. By dinnertime, I could tell it was going south. The finger with the "pokey" and the ones on either side were swollen, and the swelling was half-way down my palm. I spent a nice evening in the emergency room getting X-ray'd, doc doing an obligatory clean out, and a prescription for an oral anti-biotic. The finger has just a little swelling now, things are going in the right direction. Was the trip to the ER necessary? Maybe my body's immune system would have overcome the infection without the oral anti-biotic?

It sounds like your body may have changed a little and is less able to fight infections, as you suggest. A non-issue in our younger years can now send us to the ER.

 

[Jake M]

So, perhaps I should have considered this early and done more research.

For a hobby shop machinist (ie. a few hours a week, small stuff, basic tools) what are the risks and how serious working with stainless steels?

For general work, it's pretty much just another metal. If it stays in chips, you needn't worry. Well, keep those out of your eyeballs I guess, but not as far as your lungs go. Grinding stainless, yes, there "can" be some elevated risks, depends what you're doing, but unless you're doing something exotic, with enough horsepowers involved to be limited to commercial use, a simple dust mask is gonna solve the problem. Same goes for most metals when you're grinding. Chips are inert, coarse dust isn't even that bad, it's the stuff small enough to stay airborne that'll get into parts of your insides where they shouldn't oughtta be. Even still....... There's probably a lot worse things you experience daily. NOT saying that precautions are not warranted..... Most of us should take more precautions than we do, in ALL of our lives, not just in the shop...

I've been aware from the start that wielding stainless posses some extreme risks due to the gasses that are produced.

That's valid, but consider this- Osha sets a limit based on an 8 hour average. Then tomorrow's a new day.... I don't have the facilities to weld stainless either, but I'd have no issues buzzing a couple of things together. If there were a lot of it, forced ventilation (a stout fan blowing out one window, with fresh air entering from elsewhere...) would be plenty satisfactory.

From other reading, there is also a risk of inhalation of dust when grinding. Ok, good to know. I'm assuming that this is related to the the heat and fine dust, just like welding. Hot fine dust is going to change chemically and you don't want to inhale chromium or lead. I don't do a lot of grinding but will be more careful in general about grinding dust.

I believe that this is not heat related, but dust related. Then there's also the grinding consumables. That's stuff gets in the air too, and again, after LONG exposure, can build up to something. Forced ventilation, taking the grinding area air out in a direction AWAY from your other machine tools is beneficial for them, and in a non-production environment, is likely a solid benefit to you as well. And again, a dust mask is quite appropriate here. How far you should go is based on how much you're doing, and what your end goals are.

How about machining stainless? I imagine that small smoking hot chips of stainless are also going to be giving off bad smoke that you don't want to be inhaling all day. In the past I've machined SS at feeds and speeds that produced too much heat - to the point of blue chips and smoke. The simple fact that this is bad for end mills and small machines, I now use coolant system and my tools and myself are much happier milling SS.

If you're making chips, you've got no worries unique to the stainless. If you're cutting is making dust? Well, you're burning up cutters too fast, and not cutting efficiently..... But the fumes you see are oils, from the cutting oil you might have used, right to the simple skin oils that are on the part from your having put it in the machine. Unless things are going horribly wrong, machining isn't so bad in that department. (Do still respect the oil smoke thing... That's not exactly healthy...

So I've managed to mitigate this hazard simply by doing a better job - adding coolant and slowing down if necessary.

I don't recall seeing coolant fumes anywhere on the food pyramid.....

What about band-sawing? I use a cutting wax stick for lubrication/cutting - again, the blade lasts much longer. However cutting will still give off smoke but I'm assuming this from the wax/oil and not likely to be (much of?) an SS smoke/dust exposure hazard.

The bandsaw is a hard, case by case call. They can make dust, or they can make chips, or anywhere in between. If it's floating off into the air, it's dust. Otherwise, it's chips. If you're breathing them in and it smells/tastes like metal... It's dust. If it's so fine that it's a PITA to sweep up, it gets everywhere, but it's not hanging in the air- it's little chips.

Understand that I'm in my 60's and I've done plenty of things that exposed myself to hazards that I shouldn't have. I try not to needlessly add exposure risks and in this case, I'm now doing enough work with SS that I need consider more opportunities for repetitive exposure (but still not 9-5 job in a metal working shop level).

Life is hard. We live on a planet that is trying to kill us, in a solar system that is trying to kill us, in a galaxy that is trying to kill us, and all while being threatened by another galaxy that want's to kill us, inside of a universe that's trying to kill us...... The goal isn't to make life perfect, the goal is to not take in anything faster than what it can be gotten rid of. That ranges from "never gotten rid of", to "goes away quite quickly". I don't want to sidetrack from what you're specifically asking, but honestly, aside from welding, the "fix" is the same good practice as for EVERY metal you cut. While stainless in "SOME" situations (including welding) can have some very tangable consequences, most of it's consequences have little or nothing to do with the alloyed metal content, and more to do with the coolant, oils, and the physical dust particles, regardless of their composition, with the dangers having more to do with their size and concentration. What I believe you're after is not to be "perfect" in doing what's right (heck, even sunlight's too dangerous for peoplel these days...). but while not perfect, I think you want to do pretty good to look after what you've got right now. And I think venting (or even a little dillution if you're not welding) of the fumes, so long as you're not welding will cover that, and keeping the physical dust of ANY makeup out of your lungs, including with the stainless, and any metal, and grinding paraphanalia will get you where you want to be in that department. Cross ventilation is a very, very powerful tool in all of these battles. And a hepa equipped vacuum cleaner at the ready.