Toxic effects from galvanized food preparation utensils, p2

A. Hi, Zak. Unfortunately it's hard to say. Who knows what the old washing machine is made from and what surfaces may be in it. It's possible (perhaps unlikely, I don't know) that there is cadmium or lead on the surface for some reason. The general principle is that when we use something for a purpose for which it wasn't intended, we take risks because the designer had no intention of it being used as a smoker and there's no good feedback system in place to learn if people are getting sick from similar stuff.

I am not a scare monger or chemophobic myself . . . I just have no idea what the old washing machine might contain.

Regards,

A. Hi, Monica. We both just conceded "plausible deniability" :-)  -- so no, it's not okay.

Some people perhaps think California is doing a public service by warning people that virtually everything is dangerous in one way or other; but many of us who have taught safety courses, and know for example that mechanics are obviously not going to scrub their hands every time they touch a zinc plated nut or bolt, think that California is doing a great disservice by constantly crying wolf to the extent that they are ingraining & reinforcing the habit that we can simply ignore such warnings. California fruit flies :-)

It may be a bit harder to find, but aluminum wire might be best and is inexpensive. Stainless steel stranded wire would be safe and they make it stranded for less springiness. Anything labeled craft wire is probably safe, although wire that is not aluminum, and is not stranded, might be too springy.

Thanks for your great patience in reading this whole thread, it's gotten beyond long.

Regards,

A. Hi, Peggy. In view of the previous discussion that you are expanding upon, I think you are not asking quite the right question. I think the question you should be asking is: "Should we continue to use galvanized wire for this application?". And my reply will be: "No, you should find stainless steel or nickel plated mesh".

When you pose the question you have posed there are 1001 nuances, and all you can get are opinions from people (including me) who don't know all those subtle little details. Personally, I'd eat the dried apples though. Waste not / want not.

Regards,

A. Hi, Kim. I personally think it would be fine. It's not 100% amenable to logic; people have to pick their own fears and phobias :-)

Hi, Paco. If it's spangled like an ash can, it's probably galvanized. If it looks like it's dipped in zinc, drippy like a roofing nail, it's probably galvanized. Sorry but your inquiry is a bit cryptic. You have a commercial grill, an old grate, a piece of sheet metal, a drum, or what? Good luck.

Regards,

A. Hi, Laura. My statements are nothing more than personal opinion and, like all opinion, is driven by my own personality -- which is generally pragmatic: which means I don't think you should install a galvanized countertop, but if you have already done so, I don't think you should rip it out :-)

zinc sheet ⇦ this on eBay or Amazon [affil links] and galvanized sheeting aren't really the same thing. The zinc sheet used in the old mansions (and in some current zinc countertops) is solid zinc through and through, whereas galvanized sheet is steel sheet metal that has been dipped in molten zinc. Galvanized metal is sometimes subsequently dipped into a very dilute solution of chromic acid and, although the amount of hexavalent chrome that is possibly on the surface is very very minimal, I don't think we should design any hexavalent chrome into a surface that could have food on it. The same with the very minimal amounts of lead and cadmium that might be in galvanized sheeting. Further, I don't think that that bright spangled look will last very long with detergent washing, food spills, etc.

While I believe galvanize.org to be an honorable organization, remember that they are a trade group eager to promote the use of galvanized materials. I certainly don't believe they would deliberately conceal serious hazards, but they are not the place to get neutral, carefully balanced opinions comparing the benefits of one material to another either.

Although it's a matter of taste, with so many other choices available, from butcherblock to Corian to granite to porcelain tile to Formica to solid zinc to stainless steel, I wouldn't install galvanized countertops.

Regards,

Thanks so much for your response! This is actually for a kitchen table, not the countertops. This was a wood table we had made that was done wrong and it's really messed up. Rather than buying a new table (since we're $900 in for a really bad custom table), we're trying to come up with an inexpensive and contemporary style solution. It has to be a custom table b/c of it's size - 55" x 36", so we don't want to go through that again. I wasn't really wanting stainless b/c ALL of our appliances and hood are stainless and it seems like it'd be overkill.

The solid zinc -- is that something that can cover the current wood top? I looked into tiles, but when I priced out tiles I liked, it was going to cost another $500 if I did the work myself and then I didn't have a solution for an edge, so would have to hire someone to add an edge to the sides. If we're going to put more money into this table, whatever we do needs to look really great!

Thanks again so much for your time on this.

The solid zinc comes in sheets like the galvanized, but isn't as easy to find because it doesn't have as much general utility as galvanized sheet; and I'd guess that it's significantly more expensive.

Regards,

Q. Once again, Ted, - thank you! The guy that will hopefully help me do this top mentioned a mill-finish stainless also known as 2B. Any feedback on that? He's never worked with zinc, so I don't know if there is a difference in working with the different metals and a concern for how it'll come out.

A. Hi, Sarah. " . . . and avoid death by zinc poisoning?" What?!

Just because it looks like galvanized doesn't mean it is -- it is almost surely tin plated -- absolutely non-toxic; it will be okay. And even if it is galvanized, and there was some question of whether that is fully appropriate for certain applications, "death by citrus juicer" is only going to happen if somebody wallops you on the head with it :-)

Regards,

I'm also interested in using galvanized steel for projects involving cooking. Can you tell me the temperature at which the zinc starts to put gases into the air, or are there too many variables for that?

A. Hi,Jim.

I think you'll find that the pineapple and mandarin orange cans are actually tin plated rather than zinc plated. I'm not actually sure why they have that mottled look, but I'd guess that the tinning is done by hot dipping, similar to zinc galvanizing, and the crystal pattern arises during the cooling in the same way.

Regards,

A. Hi, Amy. I don't think you will find any authoritative studies, and will have to rely on guesses, pragmatism, and analogy. So until someone finds or does an authoritative study, my feeling is that what you did is completely harmless. Zinc is an essential micronutrient, not a poison.

Regards,

A. Hi, Shawnie. You should try to track down who authored that revision note and find out their reasons and their evidence. Asking a third party to challenge an opinion written by an unknown person based on unknown evidence is usually not an effective idea :-)

But I have seen it written myself at
www.woodheat.org/safety/rulesforfluepipes.htm: "Galvanized flue pipes must not be used because the coatings vaporize at high temperatures and release dangerous gases".

I have also heard that the manufacturers don't recommend galvanized flues for solid fuel appliances (they can probably get very hot in a chimney fire, which wouldn't apply to gas appliances. But, since the black is more costly, is it possible that it's simply thicker and therefore safer from burning through?

But if it proves impossible to source anyone who really has done exposure studies, they are probably reasonably safe for wood appliance chimneys from a zinc exposure standpoint. I certainly wouldn't try to save $15 this way on a wood stove installation in an affluent suburb; but when your choice is, as you put it, two families with galvanized flues vs. leaving one family without a stove, it sounds like the humanitarian choice.

Regards,

A. Hi, Nate. As mentioned several times, there are few facts on this subject, only personal perspectives. But I personally can't see any harm from zinc at 225 °F with no food contact.

Regards,

A. Hi, Mark.

Again, we're on the lookout for, but not finding, authoritative sources for such information. So, instead, all you are getting is one person's best guess. My opinion is that if this ductwork is outside of the chimney, where a mantle would be, there is little problem.

But if the ductwork actually passes through the chimney, exposed to hot exhaust gases from the fire, there is a chance of spreading poisonous carbon monoxide, and soot & creosote, and (in the event of a chimney fire) maybe even flame through the ducts. I would not rely on standard light-gauge ductwork for such an application, but only a carefully engineered Heatilator or similar design.

Regards,

A. Heh Heh Hello Marylou (showing my age) ...

To my knowledge the only people ever known to get metal fume fever are welders, due both to the very high temperatures of welding (above the vaporization temperature of zinc) and the intimate and prolonged exposure to the fumes. The surface of your stove itself probably never gets hot enough to vaporize zinc. A wall protector of galvanized material would, in my opinion, be harmless. Examine your wood stove's ash tray: my Jotul ash tray appears to be galvanized and the galvanizing is not melting off, let alone vaporizing off.

Regards,

Hi, Anil.

Yes, lead is poisonous.

Chrome is poisonous only in hexavalent form; in trivalent form it is an essential nutrient that we normally don't get enough of ["Chromium is an essential nutrient required for sugar and fat metabolism. Normal dietary intake of Cr for humans is suboptimal." --nih.gov].

Zinc is certainly NOT poisonous; rather, it is an essential micronutrient ["Zinc is an essential mineral that is naturally present in some foods, added to others, and available as a dietary supplement" -- nih.gov]. Let's not confuse metal fume fever, a problem experienced by welders who inhale clouds of vaporized zinc because welding temperatures exceed the vaporization point of zinc (1665° F) with day-to-day usage. That's like saying no one should ever take an aspirin because eating a bottle of 300 tablets is toxic.

Aluminum will certainly be better than zinc for certain applications including food contact surfaces, and less satisfactory than zinc for others. But I think that substituting scare tactics for a careful engineering evaluation is the wrong approach . . . further, because zinc is an essential nutrient, whereas aluminum has absolutely no place in the human body, that tack may backfire :-)

Thanks and Regards,

A. Hi, Katy. I think it's safe enough, but that it won't hold up well at all in the highly alkaline environment of a dishwasher. Stainless steel would be a lot better, and you should be able to find some on line if not in a local hardware store. Good luck.

Regards,

A. Hi, Cindy.

You are almost surely not consuming dangerous amounts from a little swizzle stick, but food service items should not be made of galvanized metal. I'd suggest a redesign with stainless steel.

Regards,

Hi Mike. Thanks.

I don't see a claim on this particular thread that no one has ever died from zinc fumes, but this is a big site with more than 50,000 threads, and postings from a quarter million people, and it is possible that such a claim was made. I'm very much on the fence on this subject because it's possible that no one has died on the spot, but if someone dies from pneumonia and the pneumonia occurred because of, or was aggravated by, zinc exposure, then I'd call the zinc exposure the cause of death.

I've seen this Paw-Paw story before and appreciate you publicizing it. But I would be much more comfortable with it if there was a medical examiner's report or something from a medical authority or police authority rather than just guesses from his friends. Since no crime was involved, though, that probably won't happen. I suffer from emphysema myself, which I blame on smoking (I never did metalwork), and I have to be careful of pneumonia too. But any air contaminant at all can be a problem; someone blowing out the candles on a birthday cake can be intolerable, for example. I do not dismiss the possibility that zinc fumes were involved in the death you mention especially when the exposure was not incidental but a deliberate effort to vaporize all of the zinc on a large batch of pipe, and the white clouds of zinc oxide were apparent; it's just that when you have emphysema, which makes you very prone to easily contracting a fatal pneumonia, it is complicated to try to blame the pneumonia on any one particular thing without solid evidence. Thanks again.

Regards,

A. Hi, Jill Ann.

This is way below the melting point, let alone the vaporization point, of zinc and should pose no problems at all. However, be very careful that there are no "sealed" fittings, as the vaporization point (boiling point) of water is 212 °F, and water sealed inside something can certainly explode.

!! But kitchen ovens should be reserved solely for food service. That's harsh I know -- but it's just not a good idea to try to decide which facets of what hobbies and home & auto repairs can be pushed how far in your food oven. It's human nature that if you don't get a separate oven the first time, you never will; and with each project you'll keep pushing it further and further :-)

Regards,