Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
-----
Danger of eating rust?
SUMMARY:
The casual and occasional ingestion of rust is not dangerous, with the possible exception of people with hemochromatosis, a rare disorder that causes excess iron accumulation.
But everyone gets to have their say in this rather long dialog which includes references to authoritative studies, as well as unsubstantiated personal opinions from the editor and others :-)
Current question and answers:
Q. I pulled out a pie dish I use infrequently and saw that there appeared to be some minor rust spots on it. I washed it with a scour pad and dish soap without results so I decided to give C-L-R a try. This was a mistake and I appear to have stripped the shiny finish off the dish. I've tried googling to see if this would affect the safety of the dish but haven't found any results. I don't expect to be able to restore it because the CLR that has stripped the metal itself. Thoughts?
Vanessa Peter- Toronto Ontario
December 27, 2020
A. Hi Vanessa. If you were fielding a question from someone whose cake didn't turn out, and you asked them how much flour they added, and their answer was they used two cups of "that white powder stuff with a sweet smell", you would interrupt to confirm that they had added flour, not confectionary sugar or roach powder :-)
You originally posted this on a thread about repairing damage to aluminum cookware, but similarly we need to first confirm that you are actually talking about aluminum -- which became questionable because aluminum cannot rust. When aluminum corrodes, it never generates that orange brown stuff. As step one, please test the pan with a magnet because I suspect that you are talking about a steel baking pan, probably with tin plating.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
December 2020
Hi Ted,
You're absolutely right. I tried the magnet trick and indeed, it is magnetic. We're not talking aluminum anymore.
- Toronto, Ontario
December 31, 2020
A. Okay, Vanessa, we moved your question to a thread about easting rust. Most bakeware that isn't non-stick teflon is probably tin plated. Tin plating is whitish and reasonably metallic-looking but not really shiny like a truck bumper ... and it is completely food-safe.
Your situation now is that the pan will rust to some degree if not kept dry and lightly oiled with a food-safe material like cooking oil. But you probably could 'season' it by baking cooking oil or bacon grease into it. The rusting, if allowed to continue, will make your cakes unsightly before it makes them dangerous.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
December 2020
⇩ Related postings, oldest first ⇩
Q. Dear Sir/Madam,
We use Stainless Steel Flatware (Spoon, Forks and Knives) for eating while at home. I have been under the impression that by using SS flatware in Dishwasher the former shall be prone to rust. However I have been using the dishwasher since long to clean my flatware. of late I have noticed that many of my spoon forks and knives have rusted. I have confirmed and they are certainly rusted. not have found the pattern we use, we are reluctant to replace these flatware unless we find new flatware with the same pattern. hence my family members and I have been using this flatware for eating. the rust has appeared in places of the flatware which is directly in contact with the food we eat. this has raised fears in my mind that I might be poisoning myself when eating from such rusted flatware.
I would like to be informed whether eating out of such rusted flatware might poison me or lead to any health hazard. if it is so I shall refrain from using such flatware as I would not like to put a few lives at risk. this in mind I have contacted you with the confidence that you shall be of valuable help in this regard. looking forward to your prompt response.
thanking you
With best regards
JIMMY
JACOB JIMMY- MUMBAI, MAHARASHTRA, INDIA
2003
A. Hi Jacob. I remember my grandmother reciting the old mantra "you'll eat a peck of dirt in your life". There is no need to worry about the rust spots; your stainless flatware will not poison you. I don't worry about rust myself -- and we use a bunch of grandma's rusty old can openers, tongs, and so on that are plain steel, not even stainless steel :-)
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003
Q. Dear Ted,
We would like to thank you for the information provided by you. As mentioned in my previous mail, I have noticed and verified that the same flatware we use is rusted. However we at our family are still using the flatware. I would be obliged to you if you could provide with information, as to whether eating from such rusted flatware is potentially dangerous and hazards to health. If so please let me know in detail because right now I am under constant fear and apprehension that I might be slow poisoning me as well as my family. Also would like you to mention the journal quotes regarding health hazard caused by the same enabling me to study in detail. Looking forward to your prompt response. Thanking you
With best regards,
JACOB JIMMY- MUMBAI, MAHARASHTRA, INDIA
2003
A. Hello again Jacob. I have already said that my family uses rusty utensils too. They are harmless and your apprehension is misplaced.
This is a public forum about metal finishing and I have no special qualifications for composing medical reports, so please go to a library that has the particular journals you have confidence in and look it up yourself :-)
If anyone else feels that it is something to worry about, we have plenty of space here and will be more than happy to print their reply! But sorry, I simply cannot spend my limited time visiting a medical library to generate a research report for you on something that I know is not hazardous just to prove it's not hazardous via medical journal quotes. Apologies :-)
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003
2003
A. Hi Jimmy,
That was a good reply you got from Ted ... and I wouldn't dare argue with him as he's 6' 4" tall !
I think that many people using stainless steel cutlery will have noticed rust marks now and then ... some 'stainless' will not rust too easily but some knifes, for instance, show rust marks BUT they are invariably made, I think, from a low grade 400 series AND they take a good edge and stay sharp.
May I suggest that you go to a local sheet metal shop because they should have mesh 'pads' they'll use, especially for aluminum and stainless, to remove scratch marks somewhat. I occasionally use them to remove the minuscule rust marks on some of our knives.
Also rust is iron in its NATURAL state ... and I wouldn't think that mini amounts of it would harm you. However, probably curry in excess might do so!
Freeman Newton [deceased]
(It is our sad duty to advise that Freeman passed away
April 21, 2012. R.I.P. old friend).
Dear Jimmy,
I just opened a can of food for my daughter with a screwdriver (because our can opener just broke). After I got it open, I noticed a small rust stain on the tip. I made my daughter something else to eat. Then I ate the can of food so it wouldn't go to waste. At this point I thought that it was pretty stupid of me to eat something that I thought might be hazardous to begin with, so I went online to find out if it is indeed hazardous (tetanus was my concern). I've had absolutely no luck finding out anything substantial.
I was searching for about 30 minutes when I came across your correspondence here. I can't believe that some from the "The home page of the finishing industry" told you to "look it up". Like there would be any other way to reach something as obscure as "The home page of the finishing industry" if you weren't actively trying to "look it up".
I want you to know that I can't believe the response you received. I hope that all of your experiences with Americans aren't like this was. I am NO expert in my field (educational multimedia production), but I help anyone who asks to the best of my ability.
Just one question: If you were worried, why continue to use the flatware until you found a concrete answer?
Ed P [last name deleted for privacy by Editor]multimedia production - Eugene, Oregon, United States
2003
Hi Ed. I answered cousin Jimmy's question to the best of my own knowledge, replying that the rust is not anything to worry about.
It is certainly Jimmy's right to not be satisfied with my personal opinion; but he then made a polite demand that I promptly conduct research, and provide journal quotes regarding health hazard caused by the same and in detail research. I replied again that my own family uses rusty utensils -- and that if he needed that kind of in-depth research he'd have to locate those journals himself. I included two 'smilies' so he'd understand the friendly light tone of my answer.
Nobody has closed the discussion, please contribute what you wish! But it's a world of limited resources, endless things need our attention, and a half-dozen new inquiries are sent to this site every hour around the clock . . . I simply cannot spend a day at a medical library to conduct a research project for him to prove it as he has asked.
I've answered hundreds & hundreds of questions from the city of Mumbai, and thousands upon thousands from the Indian subcontinent -- you shouldn't feel obligated to apologize to the people of Mumbai on behalf of the people of America for me, Ed. Rather, help him to the best of your ability as you promised you would by going to the library and finding those medical journal articles that he wants. We'll print your findings here and pass them on to Jimmy. If you can't find the time to do so, please don't apologize for others who also can't find the time :-)
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2004
A. There are many websites with information pertaining to Tetanus which do not include a single sentiment related to the ingestion of rust, therefore, without conducting test yourself (of which many extensive tests have been conducted and published by various private companies) you can deduce that rusty objects are not toxic if ingested. Please note that there are products that do produce toxic substances when they come into contact with rust.
Kristan Wifler- Burlington, Washington
2004
A. You will get a little iron in your diet, that is a good thing. We use an iron skillet all the time and so did my mother. I have been around for over 50 years. Don't worry Just eat well.
Chuck Crouser- Athens, Alabama
2004
Q. We have been boiling water in an enameled cast iron kettle. I just discovered that the bottom surface on the inside of the kettle has rusted. I have been suffering with a sudden onset of asthma. I am 52 and have never been asthmatic. Could there be a correlation between the rust contaminated tea water and asthma attacks?
Francesca Weisskindergarten teacher - New York, New York
2006
I think the original question was a good one and deserved a sincere response. A simple "I don't know" would of sufficed. As opposed to a snide, "you'll live" response. I'm sure the gentleman utilized this site for info and if you just said, "I don't know", he would have moved on to do other research.
Sharon N [last name deleted for privacy by Editor]- Coon Rapids, Minnesota
2006
But Sharon, I do know: Rusty stainless steel flatware is nothing to worry about. Please don't demand that I reply "Sorry, I don't know if it's poisonous" when I am very sure that it's not.
News agencies & politicians profit from promoting paranoia. We stay up for the late news if the teaser is "Toxic Timebomb in your kitchen?" but not for "Harmless after all", so the news business never runs items of reassurance.
The result of this relentless drumbeat is that people are fearful of everything they could possibly eat with -- aluminum, Teflon, plastic, pewter, bronze, cast iron, etc. To the extent that now Jimmy is even "under constant fear and apprehension" of stainless steel of all things! And if anyone suggests that it is harmless as I did, we're attacked with "You don't know that! Admit that you don't know!", and any attempt to reassure or lighten it up is interpreted as "snideness".
I was listening to NPR the other day. A noted psychologist explained that humans have perennial psychological needs, and that as religion is increasingly abandoned, something "psychologically similar" to the unknowns of religion must fill the vacuum, and that what is filling that vacuum is paranoia. Between that NPR show and Jacob's "I am under constant fear and apprehension that I might be slow poisoning me as well as my family" I think I'm sold :-)
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
After cleaning my bar-b-q grill and seeing the racks that have sat out in the humid weather here under the cover of the bar-b-q all year I realized that rust must indeed be ingested by many, and in large quantities that we cannot see. As we do brush the crusties off the grill, inevitably we expose more rust. It is especially noticeable when a buttered bun comes off with lines. Well, we are not dead, however the toxicity will never be known unless we conducted an experiment. As many of us smoke or drink coffee, the taste buds have a tinny flavor most of the time, and metals would be hard to detect. If it interferes with your digestion, then be on the look out for the source of your unfriendly meal, avoiding the same in the future.
Lillian Joubert- Port Alberni, BC, Canada
2007
I just noticed while looking at the bottom of my Betty Crocker kettle that the element has rusted in many places and that there was a lot of rust residue at the bottom of the kettle. Like others in the column, this rust have been ingested with my coffee, did worry me. I have sent an email to General Mills about this subject and I am waiting for a response. Will keep you updated.
Renee from Montreal
- Montreal, Quebec, Canada
2007
August 7, 2008
Hi...Here I am back (last September 24/07).... General Mills asked me to send back the kettle to have it analyzed and sent me a brand new beautiful kettle and toaster, not Betty Crocker's but Beaumark set, higher quality and style.
I was thrilled about that but I had asked to receive a report of their findings, which never came.
I must follow up just to see if they will provide me with a report.
Renee from Montreal
- Montreal, Quebec, Canada
I obviously wasn't the 1st person to wonder if rust ingestion would harm me. I'm sure I won't be the last. I am not a person paranoid that toxins are chasing after me nor would I like Ted to waste his life freeing the world of their socially induced thinking and paranoia. I just simply stumbled across this site like many others before me in search for the answer as to whether my recent ill feeling was related to discovering that the opened and refrigerated can of fruit I just ate out of two days ago had some rust around the inside of the can. I had not noticed it at 1st and wasn't really concerned after I had already eaten and did notice it. When you start feeling bad sometimes in your mind you do start to wonder if you may have eaten anything or done anything to contribute to the problem. That's only natural.
I was a bit amused, concerned, and surprised to see the slight conflict going back and forth about the initial question of the rusted eating utensils. I completely understand the reason for the request of the medical information concerning the issue, although it may not have been necessary. I think that all that was really wanted or needed was a explanation of why rust was or wasn't something to worry about ingesting. Kristan seemed to give a short, simple, and reasonable explanation for why it is probably not something to worry about. Ted's initial response was not as direct as what you expect or are used to getting from a medical informer. I believe he meant well and tried to answer the question in a way as to say "ease your mind about it", and we probably should. This did not include a direct yes or no or even any explanations as to why he thought what he stated were his thoughts. Many people respect doctor's in their professions but are still aware that their thoughts and feelings are still human and subject to error. General explanation clarifies these thoughts for the person seeking information. He may have not understood the reason for further questioning but the answer would leave most feeling like they were not informed much more than if they had picked up the phone and just asked their neighbor what they thought about it. Providing research on the answer may be worth more than the answer so I can understand not wanting to go that route but when people spend a lot of time looking up information to finally get to this site it would not seem like too much to ask just to get a small explanation.
Whether it was meant or not the tone of Ted's last few responses to this issue seemed more annoyed, defensive and condescending rather than reassuring, informative and confirming. This is my 1st time on this site. I don't know how this normally works but I hope to see less conflict surrounding future responses if I choose use this site in the future.
Sha Hunter- Atlanta, Georgia
2007
Sha, I appreciate that you spent time searching before you got to this site. Even still, I'm certainly not a "medical informer". This is a public forum focusing on metal finishing. People ask questions and anyone anywhere answers. But when no one else has replied to a posting, I try to do so as the site curator because it's common courtesy to acknowledge the postings. If you find any info, we'll be happy to print it! Thanks.
We've managed to stay "on the air" for 16 years and through 60,000+ threads by not printing any ad hominem comments -- they invariably degenerate as you can see in the public comments section of any you tube video or on-line news article.
I made an exception and printed criticism of my response, talking myself into considering them "site suggestions". But now you've seen what happens; it just goes on & on & on and the thread becomes more about an individual than the topic :-(
So we're done; if readers dislike me or my answer, sorry; but this thread has to go back on topic. Thanks again!
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
October 14, 2007
My son is renting a home built in the 1980's and it has the original dishwasher. The racks are so rusty that the rack posts are falling off in the wash cycle. I have been looking for documentation to back him up in requesting a new dishwasher and have not found anything. Does anyone know the hazards of washing dishes in this type of environment?
PJ Coulterhobbyist - Sacramento, California
2007
2007
I did a gig as a home inspector for a year or so, PJ, and I don't think any home inspection company, testing organization, or regulatory body considers the life of a dishwasher to be 20 years :-)
I'd suggest taking the tack of trying to tell the landlord that a 20 year old unit is unsatisfactory, rather than trying to prove that the rust poses a danger. Good luck.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
I would estimate that the dosage of metal is small if you can't taste it or get sick within twenty minutes of eating and entering your bloodstream. The bigger, and probably obvious issues are if the flatware can be cleaned well enough, and what kind of metal are you eating. Plain old iron is abundant in nature, and I would think is only absorbed by your body at a modest rate. Now they have discovered aluminum in Alzheimer's patients, but I would suspect the control patients as well. There are even publicly funded messages in the media now about not breathing flatulence. I don't recommend it either.
I'm guessing that you already made the decision not to use the flatware anymore, and you mainly wanted the proper reasoning behind it. My advice is to stop using them until replated by an expert, and then use them with pride.
- Chicago, Illinois
2007
Hi, G. Thanks. Although silverplate is routinely plated and replated, I've never heard of stainless steel flatware being plated or replated; and we have several threads on line here about brand new stainless flatware constantly rusting (letters 15689, 18486, 23891, and 29294 for example); with many people reporting that they have been unable to find any stainless flatware that doesn't rust anymore. :-(
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007
I, too, stumbled upon this website looking for answers to the question about ingesting rust. Inspired to continue searching, I stumbled upon the following website:
http://www.realsimple.com/realsimple/content/meal/0,21770,1619581,00.html
What I thought particularly useful was the fact that they cited an apparent expert. Here's probably the most useful quote from that site:
"If you accidentally cook on a rusty surface, the food may acquire a metallic taste, but it won't warrant a trip to the ER, says Elena Juris of the American Association of Poison Control Centers."
- Fullerton, California
I found Tom P.'s response very helpful-I followed the link and learned that Cream Of Tartar + water can help remove some rust. I wasn't terrified of ingestion, just wondering because the pan seemed to be giving off a lot and was wondering the effects. I cleaned the pan gently with cream of tartar and water, and it removed some of the rust and lessened the amount of rust particles/ residue that came off when wiping/ using. I'm about to use it now!
Kate M [last name deleted for privacy by Editor]- Austin, Texas
June 7, 2008
S |
Call it O.C.D., but Teflon or any surface I cook on must be an impartial element giving off nothing into the food. A look at the chemical reaction has the answer. Chris Kydd- Encinitas, California March 5, 2008 May 2, 2008 Hi, Chris. I certainly have no issue with people who wish to not use Teflon cookware. But out of curiosity I do ask what you consider to be a safe material to use. Regards, Ted Mooney, P.E. Striving to live Aloha finishing.com - Pine Beach, New Jersey |
S |
Stumbled onto your site because I was curious about the possible effects of my old Revere Ware tea kettle that was producing green water from the oxidized copper bottom that had apparently penetrated all the way through to the surface that touches the water. Needless to say, I threw out the old kettle and went to Costco and bought a new one. It was my impression that Revere Ware was lifetime cookware, but that's apparently false where the kettle's concerned. Tea drinkers beware. Cherie Swanlund- Fallbrook, California July 3, 2008 Hi, Cherie. Copper pots are a bit different than stainless steel flatware, and not considered a food-safe surface. Your tea kettle and similar cookware probably originally had a tin plating on it. Restoring the tin is an "old world" trade for a very long time. You might find letters 25553 and 29192 interesting. Good luck with the replacement! Regards, Ted Mooney, P.E. Striving to live Aloha finishing.com - Pine Beach, New Jersey |
Perhaps the concern here is not so much over cause and effect (i.e.. does rust harm me) but rather the broader issue of correlation (i.e.. whether or not rust harms, is rust usually found with something that IS harmful, and therefore is rust a good sign that here is something bad and I shouldn't use the utensil).
Eg. a I step on a rusty nail or knife - isn't this the usual reason why tetanus shots are encouraged? It's not the rust, it's the fact that it has been there so long it has rusted, therefore it has been there long enough to pick up harmful organisms that might hurt me. Similarly, a rusty BBQ might imply an old BBQ, hence lots of cancer-causing leftover stuff not properly cleaned off over the years, hence making an otherwise less dangerous pit more dangerous to human health.
- Johor Bahru, Johor, Malaysia
August 16, 2008
September 7, 2008
I came across this discussion in the course of seeking information to either support or refute my wife's contention that rust (in fact, ANY ferrous iron other than stainless steel) cookware causes cancer. We recently married late in life, and her carbon steel phobia has led to the disuse of an authentic Chinese wok; a set of very high quality carbon steel Sabatier kitchen knives; and all of my mother's, aunt's and grandmother's cast iron cookware. Nothing but "stainless" (which we all know isn't REALLY stainless) steel for my better half.
My search for any shred of information even remotely suggesting a link between rust on cookware and cancer (or any other medical condition known to modern science) has proven absolutely fruitless. My own solution is to humour the wife and use the el cheapo "stainless" knives when she's around, but when she is traveling and I am cooking only for myself -- out come the Sabatiers and the cast iron pots and pans.
In short, my most diligent searching has disclosed nothing that even suggests eating of slightly rusty carbon steel utensils has any deleterious health implications.
- New Haven, Connecticut
November 11, 2008 Hi Ted, - Dubai UAE November 2008 Thank you, Adrian. For a skillet, you can nearly completely prevent rusting by keeping it well seasoned with cooking fat or oil. letter 4988 offers several people's suggestions for the best way to season cast iron skillets. Good luck. Regards, Ted Mooney, P.E. Striving to live Aloha finishing.com - Pine Beach, New Jersey |
Thanks to all for the comments, suggestions, etc.
We use cast iron skillets all the time, and one was really rusty when we got it. I don't worry about using it at all now.
We recently acquired a Hobart 1/2 HP meat Grinder that is really, really old. When my husband found it, it was very rusty. We have soaked it in vinegar
⇦in bulk on
eBay
or
Amazon [affil links] and used
00 steel wool
⇦ this on
eBay or
Amazon [affil links] and now some sanding. It is cleaning up quite nicely.
I guess the main question is, would you be afraid to use the meat grinder?
Thanks for your continued support of this subject.
- Hawley, Texas
November 28, 2008
Hi, Laura
I'd probably be more leery of old meat and botulism than rusted metal. If it has been disassembled and is clean, I think it's fine. You can deter future rusting to a pretty good degree with any kind of edible oil. Try to "wax" the parts with bacon grease for example or wipe them with olive oil or mineral oil. Don't use petroleum oil (3-in-1, machinery oil) as this is poisonous.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
November 28, 2008
Rust in and of itself is not harmful to eat. It is simply iron oxide. You can find an MSDS sheet for Iron(III) Oxide, also known as rust, here:
www.iolitec.de/Download-document/534-MSDS-NO-0006-HP-Fe2O3.pdf.html
Note that the only precautions are against getting the dust in your eyes or lungs as it will be rather irritating.
The principal concern with rust is that it is often more porous and thus retains more moisture than the original material, which creates a good colonization site for bacteria, and places for dirt to hide. Additionally, since it may cause flaking of the metal, in severe cases of rusting (not surface rust like you would see on stainless utensils), you cannot clean deeply enough to reach contaminants that may be hidden behind the flakes.
In the case of the meat grinder, I personally would worry somewhat about cross contamination, if the rust is so deep that you can't get it off with a wire brush or sandpaper.
- Renton, Washington
January 8, 2009
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