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topic 7164

Is Galvanized Steel Poisonous?



A discussion started in 2001 & continuing through 2017

(2001)

Q. Hello, I work with galvanized steel and I was just wondering if it is poison and if so, what are the harmful effects that it can cause.

Thank-you

Dominic Sumner
- Adrian, Michigan


(2001)

"All things are poison and nothing (is) without poison; only the dose makes that a thing is no poison." -- Paracelsus (1493-1541)

Welding Safety

A. Hi, Dominic.

Galvanized steel is steel with a zinc coating for corrosion protection. Just as a baby aspirin a day is a healthy regimen for millions, whereas a baby eating a bottle of aspirin is a medical emergency, so too with zinc.

Zinc is most certainly not poisonous! Rather, it is an essential nutrient ["Zinc is an essential mineral that is naturally present in some foods, added to others, and available as a dietary supplement" -- nih.gov]. Cold prevention tablets and nasal sprays are zinc, and it's included in multivitamins.

When you say "work with", is it your job or your hobby? Do you mean you weld it or you just bend and cut it? If you weld galvanized metal, the coating vaporizes, and inhaling clouds of this vaporized zinc can certainly give you "metal fume fever" and possibly worse. Further, there might be very small amounts of lead and hexavalent chromium in/on the articles, and these are poisons.

If you can flesh out your question with a bit more detail about how you "work with" it, we may be able to help! Thanks.

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


(2001)

A. Dominic,

Is galvanized steel poisonous, you ask. YES, ABSOLUTELY, Don't whatever you do eat it! The harmful effects of its specific gravity on your stomach lining are enormous. It can't be digested. Mind you, you could make up a nice stew by dissolving it in acid but gastronomically this is not Cordon Bleu cooking ... and also poisonous. As long as you don't eat it, or lead, or copper, or aluminum or any metal, you should lead a normal life.

freeman newton portrait
Freeman Newton
White Rock, British Columbia, Canada

(It is our sad duty to
advise that Freeman passed away
April 21, 2012. R.I.P. old friend).



(2001)

A. How is it you "work with" galvanized steel? If you merely bend it, cut it, shear it, punch it, or roll form it; you shouldn't be in any danger. However, if you are welding it, the welding fumes are dangerous.

The galvanize coating will not be absorbed, by your skin. However, it could have a thin coating of rust preventive oil. Some people have allergic reactions to the oil. You should be wearing gloves. If the gloves get saturated with oil, get new gloves. You could also put protective cream, on your hands. Wash your hands before eating.

If you are not self employed, your company should have a material safety data sheet, for your galvanized materials.

Never eat or drink, from any galvanized product. You could get zinc poisoning. But you shouldn't be doing this, at work or home.

I also believe "lead" has been removed from all galvanize coatings. The EPA forced galvanize producers to remove the small amount of lead which was in the zinc coating.

I have also "worked with" galvanize products for 25 years. It's not something which I believe is dangerous to my health.

Good Luck,

Terry Magyar
steel co. - Columbus, OHIO


(2001)

Q. Hello.

My brother works with Galvanised steel 6 days a week, welding and bending the steel. I am concerned for his health and was wondering exactly what chemicals are in Galvanised steel and what fumes (names of the fumes?) are being given off? Are the chemicals in these fumes damaging to his health and what precautions can he take? Also if anyone knows of any web sites to MSDS that I could look at that are relevant to the chemicals my brother is being exposed to it would be greatly appreciated.

Thank you.

Heather Davis
- Sydney, NSW, Australia


(2001)

A. Heather,

A good website for MSDS sheets is siri.org/msds^ (ed. note 10/6/2017: apparently no longer on line). This site provides free MSDS information. There are other sites too if you use any web search engine like google.

Your brother is probably fine. The most hazardous chemicals he would be working with are probably concentrated acids and hexavalent chromium. Both of these are reasonably safe to work with if proper care is taken. He should be able to ask his boss for hazard information. In the U.S., we have the Hazards Communications Act in which providing this information to workers is a legal requirement. I would imagine that Australia might have a similar law.

If I were you, I would be more concerned about the safety procedures at his facility than the specific chemicals. Workplaces need to be concerned about things like railings, good ventilation, first aid kits, eyewashes, safety showers, housekeeping, and chemical handling training. If his management is responsible and concerned about safety, then I would not worry.

tim neveau
Tim Neveau
Rochester Hills, Michigan


(2002)

A. I looked up zinc poisoning on WebMD and it is poisonous. Heather, you need to let your brother know that inhaling the fumes of galvanized steel will screw you up. I was welding pipes of galvanized steel and I thought I had a major onset of the flu. If he works with it for a living the company he works for is required to let him know all of the risks and preventative measures.

Ian Davidson
- Charlottesville, Virginia


(2002)

A. Yes, that seems like the metal flu, similar symptoms to the flu, but caused by exposure to the fumes.

pooky
tom pullizi signature
Tom Pullizzi
Falls Township, Pennsylvania


Powered Air Purifying Respiratory (PARP) system

(2002)

A. Hello,

I stumbled onto your question while researching the exact topic of welding galvanized surfaces. In my research, I've found that in addition to the numerous common welding fumes that are harmful to inhale, galvanized metals give off zinc oxide when heated. Zinc oxide causes metal fume fever. Good ventilation is the key to welding! Don't breathe all those metals- your body can handle quite a lot, but it's best to minimize your health risks.

Casey Bogen
- Portland, Oregon


(2003)

A. If you are welding galvanized then you are at a great risk of getting what is called welding fume fever, the symptoms of this are identical to flu but very rarely last longer than 48 hours. If this happens to you once, then think about getting a better extraction system because if this is a common problem then the harm done to you will get worse as time goes on. The body can only take so much before it starts to fail. Also I would recommend that you do some research on the production of Ozone when welding galvanized and other metals such as stainless steel and aluminium.

Gavin Barr
- Sheffield, England



sidebar (2003)

Q. WHAT ABOUT THE OLD THING OF DRINKING MILK WHEN WELDING GALVANIZED METALS?

LES DRUMMOND
TRAILERS - DENVER, COLORADO


(2003)

Q. Les Drummond asked the question about milk. I have also heard that milk will remove the poison. Is it true or is it the by product of too much green smoke?

Randy Brown
- West Milton, Ohio


(2005)

A. I have been welding on some galvanized panels and old plumbing pipe that I am using to build holding pens and roping arena, I am also a firefighter and have the privilege to be around doctors and paramedics, I was told that if you drink milk it will help offset the poison, although you don't want that to be your primary remedy. I was also told that you can wear a charcoal respirator, I don't know how true this is but I have been sick for the last week, with the wind blowing away from me and all so I don't know.

Michael L Jordan
self employed welder - Ada, Oklahoma


September 28, 2009

A. I don't know about the milk for galvanizing but it does help after welding stainless steel.

Jeff Keen
- Claremore, Oklahoma


June 10, 2011

A. Galvanise coating is dangerous to your health if ingested (so wash your hands after handling) and if the gas off it is inhaled for example when welding. Inhaling the gas will cause severe flu like symptoms that last about 48 hrs. 'galv flu'. It also attacks the lining on your stomach. Drinking milk before welding lines your stomach and will help but it still goes through your lungs which can't be good! Best wearing appropriate breathing apparatus and in well ventilated area.

Andy Jones
- Old Colwyn, Conwy, North Wales



Welding: A Management Primer and Employee Training Guide

(2003)

Q. I work for a company that welds galvanized steel, and I was wondering where I could find information about the side effects and symptoms associated to the smoke and fumes of the galvanized steel.

Wayne Brown
- Columbus, Mississippi


(2003)

A. Hi, Wayne. We now have at least six threads about that subject on-line here; so please try the search engine at the top of the page. You didn't say whether you are the safety director for your company or an employee doing the welding. If the former, you have some work in front of you; if the latter, ask your employer for the MSDS and related safety information. Good luck.

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


(2004)

Q. Hi I have been welding galvanized steel for the last 5 years I wear a air back pack. What sort of affects could I have when I get older. I am 31 years old -- is it harmful?

Jamie Donnelly
sub/contractor - Melbourne, Vic, Australia


July , 2008

A. Hi, Jamie. I think that "metal fume fever" is a good "canary in the coal mine". If you are prudently wearing an air pack and you are suffering no metal fume fever episodes, I would not expect long term problems. However, your employer should somehow offer you access to an industrial hygienist or a doctor. Remember that these public comments are offered by people in the metal finishing industry and users, but generally not industrial hygienists or doctors.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


(2006)

i. I just want to add to the ever growing question concerning potential occupational over exposure to galvanized steel. Take note that not only do you need to look for welding fumes, but you also need to look at potential fluorides.

Shawn Jacob
- Lexington, Kentucky


Please clarify that for me, Shawn. Where are these fluorides coming from in the topic of this discussion? Fluorine is an element; it cannot be generated from any chemical reaction; that is, it cannot be released unless it was present in the first place. There is certainly no fluoride in the galvanizing, so please clarify what situation you are alluding to, and what material has fluorine in or on it -- some welding rods maybe? Thanks!

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



sidebar January 5, 2008

Q. Would the same negative affects "metal fumes" result from using a piece of galv. steel pipe in place of a piece of black stove pipe on a wood heating furnace?

I know someone who is using same and have had concerns.

TIA,
David

David A, Tobey
- Auburn, Washington


January 7, 2008

A. The exhaust ducts on gas-fired water heaters, boilers,and furnaces are almost universally galvanized, and I don't think wood stove ductwork should be much different. I doubt that the outside surface of the duct could ever reach the melting point of zinc, about 420 °C (the hottest point on the outside of my stove reaches about 320 °C); and I don't think even the heart of a wood fire reaches the 907 °C boiling point of zinc.

Still, if you read the installation instructions for wood stoves, most will tell you to use black painted ductwork rather than galvanized. But who knows if any stove manufacturer has actually seen a "fume fever" problem, or they are just reinforcing urban legend -- especially since most wood stoves, including mine, have galvanized ash collector trays :-)

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


July 22, 2008

Q. Hi,
I built a rotisserie, and needed a spit for the meat I'm thinking of using galvanized steel.
Is it safe?

Vic Askovic
hobbyist - New Jersey


July 2008

A. Hi, Vic. No, it's not "safe" because zinc is not a "food-safe" material. There should be no contact between food and galvanized surfaces. That is because acidic foods can dissolve zinc and we don't want the situation of people eating the dissolved zinc, and the possibility of overdose.

Again, zinc is an essential nutrient not a poison -- but you don't make coffee cups out of aspirin, or spits our of zinc :-)

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


July 13, 2009 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Is it safe to use zinc plated 1/4 inch rod to skewer through a pig to keep it from spinning on the rotisserie rod for a pig roast? The cook temp will be around 300 degrees but the internal temp will only reach 165 degrees.

Jason Armagost
buyer - Ridgway, Pennsylvania


July 14, 2009

A. Hi, Jason. Zinc is not a food-safe material. The temperature doesn't matter, food should not directly be mixed in or skewered onto zinc. That doesn't mean it's a genuine hazard, just that guidelines say we shouldn't do it.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


August 1, 2008

Q. In pottery we sometimes fire with saggars or containers inside a propane gas kiln or a pit. I have been firing an outside gas kiln to 1130 degrees with galvanized trash cans with lids. The cans are filled with wood shavings to smoke fire pots. I was recently told that I can no longer use the galvanized cans in the kiln because they release fumes that will damage the kiln bricks. This seems silly to me since glazes contain zinc and other hazardous chemicals and I've seen no damage to the bricks. Can you tell me if galvanized metal contains any substance that would damage the kiln bricks when heated to this temperature? Would there be harm to individuals since the kiln is outdoors? If so would a respirator take care of it? Thank you.

Carol Darnell(returns)
- Wilmington, Ohio


August 5, 2008

A. Hi, Carol. Don't inhale the fumes, they could possibly give you flu-like "metal fume fever", but you surely don't anyway. I don't know 100% about zinc damaging kiln bricks but I seriously doubt it.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


August 7, 2008

Q. Hi,
I built a rotisserie spit and made the box out of galvanized steel. I sanded and wiped the metal with vinegar and then painted the inside of the box with barbecue paint. Do you think this is safe to use or am I looking for trouble. thank you

Joey Vazquez
welder new in the trade - Austin Texas


August 7, 2008

A. Hi, Joey. I personally doubt that it's any problem. The enclosure is not a food surface. But paint fumes are not good. Get it good and hot without food in it a few times first.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


April 8, 2009

Q. Hi. My name is Shelley and I'm the mother of a 14 month-old. Currently, I do not have a bathtub, only a shower. I am wondering if galvanized steel is safe to use as a bathtub for my son. Will the zinc or other metal leach into the water where it may enter his mouth, eye, etc? Thanks!

Shelley Desai
hobbyist - Portland, Oregon


April 25, 2009

A. Hi, Shelley. The feed troughs and watering troughs on many farms are galvanized; people in remote areas have collected rain water off their galvanized roofs for many purposes, including drinking, for decades; and a great deal of water piping (maybe most water piping) was galvanized until a few decades ago. I personally don't think there is any danger whatsoever, but if anyone thinks there is, they are encouraged to post the reason for their concern.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


May 21, 2009

Q. My husband is a bystronic laser operator and just started working with galvanized steel pipes. They have a vacuum system attached to the machine sucking up the fumes. He wants to know if there is any danger of not wearing a respirator while cutting it? He has 2 fans for ventilation blowing it away. He is really concerned if he is in danger or if the people around him 2 machines over should be concerned. Please let us know.Thanks

Tammyleigh Callagy-Pitzer
- Indianapolis, Indiana


May 28, 2009

Q. Hi! I have a question - I put galvanized fencing around my strawberry patch (to keep the birds out) and I'm wondering if that's unsafe (could zinc leach into the soil, etc). In a previous post you stated that galvanized metal is not safe for food, but you also said that it's okay for bath water. Thanks in advance for your response!

Catherine Chandler
- Orrville, Ohio


May 29, 2009

A. Hi, Catherine. Galvanized fencing is fine. When we say it's not "food-safe" we mean you should not cook in zinc pots or serve food out of zinc containers because of the possibility of acidic food or drink dissolving the zinc, and you consuming too much of it. Zinc is not poison, it is an essential nutrient; cold prevention tablets are one example of the deliberate consumption of zinc.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


Welding Respirator

September 28, 2009

Q. I was wondering if there are any side effects of the actual process of hot dip galvanizing fumes. There is a company across the street from where I work and they hot dip galvanize their parts on site. Thank You

Jeff Keen
welder - Claremore, Oklahoma


September 28, 2009

A. Hi, Jeff. Most industrial facilities have exhaust systems and fume scrubbers to clean up emissions from processes like these. If you can see and smell fumes, and find them objectionable, in most areas the state EPA will make the shop correct the problem under a nuisance clause even if they do not exceed emission standards.

We can't even definitively say whether carefully monitored things consumed in definitively measured amounts like coffee, red wine, and milk are good or bad for you -- the answers seem to change every few months. So to try to estimate the possible side effects of an unknown amount of fumes from a process you're not familiar with, that are controlled to an unknown degree, on someone in an office in a different building across the street is simply impossible. Sorry.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



December 10, 2009 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Is it dangerous for my families health to use galvanized pipe for my fire place blower? The pipe is in the bottom of the fireplace so as to have the embers around it heat the pipe then a fan blows through the pipe. Can this cause zinc or galvanized poisoning from the pipe being heated by the fire?

Thanks,

Dale Huff
hobbyist - Strawberry Plains, Tennessee


December 11, 2009

A. Hi, Dale. As noted in the beginning of this thread and a dozen like it, everything is relative. The amount of zinc exposure from this sounds reasonably minimal, and zinc is considered non-toxic.

What would concern me far more is the possibility of pinhole leaks in your piping which, depending on whether the section under the coals is on the suction side of the fan, could draw carbon monoxide into the house.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


December 11, 2009

! Ted,
Thank you for the answer and your concern at this point in time the piping is still new, I have planned on it burning through in a season or two so I will be checking it regularly. Thank you again this site has been very helpful and educating.

Thanks

Dale Huff
hobbyist - Strawberry Plains, Tennessee


February 1, 2010

Q. I'm unclear of the answers somewhat. Is it safe to deliver smoke to a smokehouse with galv. pipe?

Scott Maraczi
- Winfield, Missouri


April 6, 2010

Q. I would like to make balcony veggie garden boxes made from galvanized metal. These boxes will match the house. Will the zinc leach into my soil and poison my vegetables?

Catherine Harley
- Boulder, Colorado


April 6, 2010

A. Hi, Catherine. No, it won't.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


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