Some info on Lead in Glazes

Have you seen the TikTok or Reels videos that show a person going into their local thrift store and checking plates, bowls, and cups with a little marker for lead? When they mark the piece if the mark changes color it shows that there is lead in the piece and they claim that it shouldn't be sold and they offer to get rid of it for the thrift store? 

Let's talk a little bit about lead in ceramics and in glass.  Historically speaking lead was added to the components of the glaze as a flux.  Adding the lead meant that the silica that was used to form the glass part of the glaze meant that the glaze could melt at a lower temperature than without it.  This was good because it meant the kiln did not have to get as hot to melt the glaze on the pieces.  In addition, if a artist was using a low-fire clay then during the glaze firing it did not have to get as hot, and potentially over-fire and melt the clay. Lead was also added to glass for the same reason that it was used in glazes, to lower the temperature needed to melt the silica and other ingredients into glass. 

In the 1970s in the US the use of lead in paint, gasoline, and glazes, came under fire due to safety concerns.  Lead was removed from many things including in most commercial ceramic glazes and they have remained lead free ever since! *There are a few glazes that have lead in them, for example Amaco's Potter's Choice Palladium and Adventurine.*

With this, if a person buys new mass produced ceramic dinnerware from a reputable company that is made in the US, it too is made with lead-free glazes.  Fiestaware, for example, stopped production and use of their lead based glazes in 1986.  

The FDA has established what acceptable levels of lead in different types of dinnerware to ensure safe levels for consumers.  For items like plates and bowls the RELEASE level is 3mg/liter while cups, mugs, pitchers have a release level of .5mg/liter.  What the FDA realized is that using lead in the glaze manufacturing process wasn't the issue, but rather how much lead would leach out into the food or drink that was the issue.  This leachability could be addressed by properly designing and firing (and later testing) of ceramic pieces.  

For glass it is the release level of lead is what is tested for in leaded crystal.  How much of the lead leaches into the liquid contained in the vessel. So basically, if a person uses leaded crystal once in a while, and doesn't let the liquid sit in the vessel the FDA has said its not great, but ok enough.  However, one doesn't want to store liquid in leaded crystal.  

The FDA has a very strict process and protocol in place for testing ceramics and glass, and pieces need to be sent to a lab and tested using a 24 hour soak in a 4% acetic acid solution and then are subjected to further lab testing. 

The Environmental Protection Agency has approved of 3 at home tests for lead testing, 3M™ LeadCheck™, D-Lead®, and State of Massachusetts Lead Tests.  However these test kits have been approved for use on Ferrous Metals, Wood, Plaster, and Drywall.  Nowhere are they approved for testing ceramics or glass.  The most popular kits right now on Amazon state that they are lead kits designed for testing for lead in paint.  

So when someone goes to the thrift store in the TikTok videos or reels and is testing the pieces for lead, is it finding lead? Possibly (remember its a video that someone made!)  depending on when the piece was made.  Or depending on who made the piece.  The FDA has a threshold that lead can be used in the manufacturing of glaze and it is how much it leaches into the food/drink - not that it is in the materials used! Those tests in the videos are only showing if there is lead in glaze, not how much or if it is above or below the FDA thresh hold! 

My last thought is that other countries have local artisans that are making traditional pottery, such as in Mexico for their Mexican Bean Pots.  These artisans may be using lead within their glazes and one should be aware of that when purchasing pottery from local artisans. 

So, as an artist, I do not make my own glazes, I use commercially made and manufactured glazes for my work.  These glazes have been tested by the manufacturer as to their safe-ness and suitability for use for ceramic pieces.  The glazes that I mix have been approved for mixing by the company and this does not change the safety or suitability of the glazes.  

 **Disclaimer: Please know that I not affiliated with any clay or glaze companies. That which is posted here is from my own reading and understanding of the topic.  Please be sure to do your own reading & research and make your own decisions on what is safe for you and yours!**