Jump to content
Sign in to follow this  
liambesaw

Misleading safety info from manufacturers?

Recommended Posts

I was looking at some commercial glazes today while browsing the internet, and I noticed that pretty much every glaze had the dinnerware safe logo, even glazes that crazed and were full of copper, even metallic glazes!  I was thinking wow how did they manage to pull that off!  So I did some digging and read through a food safety disclaimer, and inside of it they mentioned

"Currently the only materials that are regulated by the FDA regarding food safety in ceramic glazes are lead and cadmium."

They also had a disclaimer stating that if you are interested in food safety you need to perform your own laboratory testing of their product.  

It just struck me as dishonest to treat any glaze without lead or cadmium as food safe, am I wrong here?  I've only read a handful of books and papers on glaze formulation, but they all stressed that a functional glaze should be "durable", and well formulated with food safety in mind.  A copper green glaze that crazes by design, or a glaze so full of metal oxide that it becomes shiny like a mirror just don't strike me as durable.  

Just curious as to what others think, because when I was in school and even afterwards we were taught that the commercial glazes were safer than ones mixed by us, so I've always had that bias until doing research on it over the past year.

Share this post


Link to post
Share on other sites

Wellthey've cleared their company of litigation issues.

I guess in the narrow field they've described to their use of "foodsafe" not dishonest.

What is smelly is hiding the i.portant to potter info in small print in a disclaimer....not actually on the label it reads.

Allowable but disrespectful of their customers

Share this post


Link to post
Share on other sites

Well sure it's legal, but if only lead and cadmium are regulated for food safety in glazes, you could add Mercury and call it food safe which just seems silly to me.  I also was shocked to see that some of these glazes are AP nontoxic but have an msds stating they're toxic.  It's weird to me, it makes me doubt the things I see.

Share this post


Link to post
Share on other sites

It's the wild west out there as far as meaningful information from Safety Data Sheets. The glaze manufactures are covering themselves by having those disclaimers and putting the liability onto the ceramic artists using their products. Getting questionable glazes tested and comparing the results to drinking water standards is the artists responsibility, even then the glazing and firing conditions need to be replicated for all subsequent firings or results can change. It's easy to rule out glazes, with both acid and alkaline home tests, but they rule glazes out not in, insofar as glaze durability or "food safe".

Share this post


Link to post
Share on other sites

And since they don't post the recipes of their glazes for obvious reasons, you can't tell if they're durable or not.  Which is just another reason to mix my own I suppose.  Just a little eye opening, in a bad way.

Share this post


Link to post
Share on other sites
3 hours ago, liambesaw said:

Well sure it's legal, but if only lead and cadmium are regulated for food safety in glazes, you could add Mercury and call it food safe which just seems silly to me.  I also was shocked to see that some of these glazes are AP nontoxic but have an msds stating they're toxic.  It's weird to me, it makes me doubt the things I see.

I think they didn't include mercury in their statement because it's not used in glazes. Imagine trying to keep that in suspension!

A glaze can have ingredients that are toxic, but are in low enough concentrations in the glaze that they're not an issue. For instance, cobalt, copper, manganese, etc.

Also, you're talking about two different issues here: food safety vs toxicity labeling. Food safety refers only to the fired glaze. Toxicity labeling refers only to the product in the form in which it is sold. So a glaze can be labeled toxic in its raw form, but still be food safe in its fired form. No glazes that are purchased as a powder are labeled 'Non-Toxic', because of the silica that can be inhaled. But those can be perfectly safe glazes for food. Some glazes that contain cobalt and/or copper can be non-toxic for adults, but not safe for children under 13, because smaller bodies can't deal with it as well as bigger bodies.

All art materials have to have toxicity labeling that conforms to the federal government standard, ASTM D-4236. Samples of products have to be sent off to a licensed lab to test for dangerous materials. Further testing is often done with specific ingredients. For example, copper carbonate may be tested for lead content, talc may be tested for asbestos. The lab then tells the manufacturer what needs to go on the label- Non Toxic, Caution (not safe for kids), etc.

As for the food safety label, there is no federal standard for that beyond lead and cadmium. When I worked for A.R.T., food safety was determined by the recipe, not by sending glazes off to the lab to be tested for leaching. I made them change several of their labels from Food Safe to Not Food Safe when I started there. There were several dry matte glazes and a couple of crackle glazes that on paper were not going to leach anything dangerous, but weren't good from a hygiene standpoint. There was also a saturated copper glaze that was clearly going to leach copper that I made them change. Glaze durability was not considered to be a factor, though, and I don't think it's a factor for most commercial glazes. The important thing to them is visual appeal. A lot of really pretty things can be done with glazes when you stop making the glass durable.

I get that there are a lot of variables with firing ceramics that are out of the manufacturers control, but it seems lazy and somewhat dishonest to me to label something as food safe, but then say it's not their job to confirm it. It's also sad that they only adhere to the bare minimum federal requirements of no lead or cadmium, when we know there are so many more issues with food safety. Imagine buying a car that the manufacturer said would get 60mpg, but that could only be confirmed by buying the car and driving it...

Share this post


Link to post
Share on other sites

Wellthe posting of this may have an effect on the glaze puechases made if the brand in question is stated .

Why protect the company with such little regard for the purchaser?

It has protected itself:-//

Share this post


Link to post
Share on other sites

Its been a problem for many many decades.I would not trust commercial glazes in the 70's 80'90's 2000's,3,000 and beyond.

It used to be that they said  the lead was incapsulated until it was removed for glazes.

The real question is how much leaches out and what that  the effects on us-really a big can of worms.I do not see this getting better anytime soon. Thats why making your own glaze makes great sense. You know whats in there.

Edited by Mark C.

Share this post


Link to post
Share on other sites
2 minutes ago, Mark C. said:

Thats why making your own glaze makes great sense. You know whats in there.

Assuming you know what you're doing. I think the majority of hobbyists would quit if they had to deal with glaze formulation. The glaze companies have created the market for hobbyists, yet they don't take responsibility for it. People assume, and rightfully so, that if they buy a glaze that says its food safe, that it is a durable glazes that won't leach anything.

The tricky part about all this is that if there are greater regulations put on glaze manufacturers, it can eventually work its way down to us, and force us to do a lot more testing and documenting with our products, which can get very expensive if you're using a lot of glazes. It's a bit of a slippery slope. The goal would be to get the glaze companies to take it up themselves, without government regulation.

Share this post


Link to post
Share on other sites
31 minutes ago, neilestrick said:

Assuming you know what you're doing. I think the majority of hobbyists would quit if they had to deal with glaze formulation. The glaze companies have created the market for hobbyists, yet they don't take responsibility for it. People assume, and rightfully so, that if they buy a glaze that says its food safe, that it is a durable glazes that won't leach anything.

The tricky part about all this is that if there are greater regulations put on glaze manufacturers, it can eventually work its way down to us, and force us to do a lot more testing and documenting with our products, which can get very expensive if you're using a lot of glazes. It's a bit of a slippery slope. The goal would be to get the glaze companies to take it up themselves, without government regulation.

That's a good goal, but I don't think regulation would have to involve people mixing their own glazes to test them all.  A happy medium could be achieved where glazes with certain ingredients (barium, copper, lithium, et al) would require lab testing, but glazes with GRAS ingredients like iron oxides, rutiles, titox, zircopax, et al could get a pass because leeching wouldn't involve a safety issue in those cases.  I wouldn't be opposed to something like that.

 

Also just to be clear, I made this thread because I was shocked that food safety means something entirely different than what I had thought and what books on the subject talk about and I just wanted to share

Edited by liambesaw

Share this post


Link to post
Share on other sites

@liambesaw

I really agree with you with respect to -  this can be made much better with some effort. With respect to compliance there are always those who see the rules for the spirit of ......... and those that use them as a roadmap to the margins. 

A decent definition of glaze durability is good and restricting potentially hazardous oxides, stains and fluxes another very positive step towards overall safety. There are many that will argue at the edge that these do not solve all the potential issues so therefore they are over restrictive and sometimes invalid therefore invalidating them in total.

Good solid reasonable rules that you propose I believe would be an improvement and a positive step while giving potters better direction on what is acceptable or likely not. The downside here is buerocratically if the rules become ridiculous, punitive and costly lots of potters simply go away.

A difficult problem to say the least. When Neil made them change the saturated copper recipe that was laudable. Seriously though, how many have that conviction? Commercial glazes for me are mostly a non starter since like advertising they are looking to sell the most appealing product while complying with standards that are poorly established but carry great names like food safe.

just what is a microwave safe glaze anyway,  No heavy metals?

Just my bloviating though.

Edited by Bill Kielb

Share this post


Link to post
Share on other sites

I decided right quick when I got back into clay that I won't make anything for use with food/beverage and will make clear that the piece is either purely decorative or functional only for non-organic items, like just to hold pencils or jewelry.  When I was building my web site and seeking input here via the Business/Marketing forum, I mentioned my aversion to claiming anything to be food safe when I could not guarantee that, and that I wasn't going to be spending money for testing.  As I recall, there was a bit of a push-back that I was being overly cautious and maybe wimping out. Trust me, I've been really happy with my decision.  On some other ceramic glaze groups, many people clearly believe that commercial glazes are safe because the mfg. says so. They get right fiesty about defending and asserting that belief. Often when someone tries to educate by providing more accurate info, it's clear that some people just don't want to hear it...but that is grossly unfair to the customer buying that dinnerware!  

Share this post


Link to post
Share on other sites
On 1/28/2019 at 9:08 PM, neilestrick said:

I think they didn't include mercury in their statement because it's not used in glazes

I worked as an intern at a community art center for a few months during college. In their "glaze closet" there were a LOT of old materials, stored improperly, and was a huge inhalation hazard...however, one of the small glass jars I came across was powdered red mercury. I had never seen it called for in a glaze recipe, but assumed that at one time it was, since it was in the glaze closet, but who knows, maybe it got donated and someone thought this was its proper home.

I know a lot of nasty materials were used historically in ceramics, which are no longer; was mercury one of those?

Share this post


Link to post
Share on other sites

Sounds a bit questionable.  a long time ago there were conmen selling red mercury but I do not believe it was ever confirmed and powdered is an even more interesting state for the substance. Freeze dried? LOL!

I think this might have been a joke.

Share this post


Link to post
Share on other sites
19 minutes ago, Bill Kielb said:

Sounds a bit questionable.  a long time ago there were conmen selling red mercury but I do not believe it was ever confirmed and powdered is an even more interesting state for the substance. Freeze dried? LOL!

I think this might have been a joke.

https://en.m.wikipedia.org/wiki/Mercury(II)_oxide

Wouldn't be too useful since it decomposes at 500c

Edited by liambesaw

Share this post


Link to post
Share on other sites

We picked up an old junker kiln years ago with the thought of using it for barrel firing, the woman giving it away had a box of glaze chemicals she wanted to get rid of too.  Everything was in white paper bags with the prices written on, one bag was uranium oxide. 

Share this post


Link to post
Share on other sites
48 minutes ago, Min said:

We picked up an old junker kiln years ago with the thought of using it for barrel firing, the woman giving it away had a box of glaze chemicals she wanted to get rid of too.  Everything was in white paper bags with the prices written on, one bag was uranium oxide. 

Uranium oxide is also food safe according to the FDA!  Now THATS a metallic saturate glaze I'd like to see haha

Share this post


Link to post
Share on other sites

The mercury might have been used as a glass colourant. They can use metals like arsenic, too, because glass is formed at much lower temperatures than what we use. 

And if you have your great grandmother’s Pyrex, the yellow and the red ones might tip off a Geiger counter. 

Share this post


Link to post
Share on other sites
3 minutes ago, Callie Beller Diesel said:

The mercury might have been used as a glass colourant. They can use metals like arsenic, too, because glass is formed at much lower temperatures than what we use. 

And if you have your great grandmother’s Pyrex, the yellow and the red ones might tip off a Geiger counter. 

My mom still has a bunch of my grandmother's uranium glassware, I don't think it's pyrex and it's not yellow or red though, it looks like a cartoon nuclear waste green

Share this post


Link to post
Share on other sites
On 1/31/2019 at 9:02 PM, liambesaw said:

My mom still has a bunch of my grandmother's uranium glassware, I don't think it's pyrex and it's not yellow or red though, it looks like a cartoon nuclear waste green

I met someone who claimed her yellow-uranium-glazed pot was so radioactive it had to be displayed in a roped-off area. 

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.