If you spend any time online reading about polymer clay you will doubtless read the ominous warnings that other clayers tell you. “Don’t use polymer clay with food.” “Use dedicated tools with polymer clay.” There is much talk of “contamination”. The labels tell you to wash your hands and don’t eat while claying. And yet we read on the label that polymer clay is non-toxic. What is going on here? What is safe? What is not? I’ve looked into the issue and I’ll try to bring some clarity and eliminate some of the fear and confusion around the question, “Is polymer clay safe?”
Is Polymer Clay Safe with Food?
If you’ve ever worked in food service, you know how there are regulations about sterilizing the utensils and surfaces. Cutlery, bowls, and plates need to be washed in suitably hot water and need to be dipped in a disinfecting bath if washed by hand. Or run though a hot dishwasher. Polymer clay can readily withstand a few trips through the dishwasher, but the heat and caustic soap of a dishwasher can cause polymer to change color or break down over time. The bleach of a sterilizing solution can cause polymer clay to change color and/or degrade. The manufacturers of polymer clay don’t make it for this purpose. It’s made to be a craft and molding material, not a food-utensil-creating material. So they haven’t invested in the testing necessary to certify it as being a food-safe material. And because they haven’t tested for it, they can’t recommend or endorse it.
Also, a polymer clay manufacturer can’t guarantee how a crafter will make a bowl, for instance. One person might make one that’s super smooth, but another person might use overlapping cane slices with lots of nooks and crannies. Such a bowl is impossible to be adequately cleaned and therefore unable to be considered “food safe”. By the way, you’ve probably read people mention that “microscopic food particles get trapped and bacteria can grow”. Well, take it from the old microbiologist here (that’s me). Bacteria isn’t going to grow in your polymer clay. It doesn’t work that way. But it can certainly hide in the crevices, cracks, and surface pits. And the next thing that goes in the bowl could certainly be contaminated with it. Think Salmonella. Ew. You need to be able to fully clean and sanitize your item if you’re going to use it with food, and polymer clay just isn’t made for that. Period.
Could you use a sealer, such as Varathane, and would a bowl then be food safe? Well…Varathane isn’t designed to be used for food contact purposes either. And also, Varathane won’t hold up to a trip through the dishwasher.
Realistically, though, is polymer clay safe to make a decorative bowl to hold some nuts or bananas or wrapped candies on your table? Probably. It’s not toxic any more than many other plastics. It’s not like polymer clay will ruin your food. But in general, polymer clay is just not suited for making food-contact items.
Covering Cutlery and Glasses with Polymer Clay
But you see lots of times where polymer clay is used to cover the handles of cutlery or the outsides of glasses. Is polymer clay safe for that? Yes, it is absolutely safe to use polymer clay in this manner. As long as it’s not a food-contact region, you’re fine. So go ahead and decorate your wine glasses and coffee cups. Go ahead and make big chunky handles for children’s cutlery. But leave the polymer clay off of the food-contact region. Leave that area clear so that it can be adequately cleaned and sanitized. Remember that anything decorated with polymer clay needs to be hand washed, too. The dishwasher isn’t kind to any hand-decorated art kitchenware!
Use Clay Dedicated Tools
If you’ll check the label of a bar of polymer clay, the instructions will tell you to use clay-dedicated tools and to wash your hands before eating. That has led many people to fear that polymer clay creates some sort of toxic contamination. First off, let me assure you. Polymer clay has been tested and is certified to be non-toxic. It is not something that’s going to make you sick when used as directed. There’s the key right there. When used as directed.
You see, polymer clay is made from PVC (polyvinyl chloride) and a plasticizer (that makes it soft…many plastics have plasticizers). And because we use PVC pipes for our water supply, there are well-established tolerances for how much ingested PVC is considered to be toxic. It’s a lot, by the way, so don’t worry. But if a manufacturer didn’t discourage you from using your kitchen tools with clay…and then using them for food again…how could they know how much PVC and plasticizer a customer might ingest? I might be very careful and clean my knife well. But another person might pick up their clay knife, with particles of clay, and cut their kids’ sandwiches. The manufacturer can’t control that! And because polymer clay isn’t food, and toxic levels are possible if you ate enough of it, they must tell you to wash your hands and use clay dedicated tools. Does that make sense? If you happen to be claying and walk through the kitchen one time and your hands end up in the bag of chips, I would not be concerned in the slightest. You’re not going to die. But don’t make a habit of it. And you really should wash your hands before eating anyway, right? If you need to use a specific kitchen tool for a project, go right ahead. Just clean it thoroughly before it goes back to the kitchen. And I mean thoroughly. Polymer clay is not water soluble and won’t come off with a quick wash.
What about Plasticizers?
There is much fear around the term “plasticizers” when it comes to polymer clay. First off, a plasticizer is a chemical that is used to make a substance more “plastic” or soft and bendy. Many plastics have plasticizers. Vinyl hoses have them. Plastic bowls have them. Your shoes have them. Even gum has plasticizer…yes…there are edible plasticizers. And one of the chemical characteristics of a plasticizer is that it tends to migrate out of the plastic over time (some faster than others). That’s why old plastic becomes brittle. It’s because the plasticizer has evaporated out of the material, leaving it brittle. Years ago they used plasticizers with a small molecular weight (smaller molecules) that would easily migrate out. Modern plasticizers have much larger molecules and stay put inside the plastic better. That leads to longer life of the plastic. The most modern plasticizers used with polymer clay are locked up between the PVC molecules when they fuse during baking, assuming it’s baked adequately.
One class of plasticizers, called phthalate esters, came under fire back in late 90’s and early 2000’s as being an endocrine disruptor. (Many cancers are affected by endocrine tissue, so this is worrisome.) Because those plasticizers migrate, it was found that it was possible for phthalate esters to be ingested. Of particular concern were baby bottles and children’s toys (because kids chew on their toys). So there was a campaign to eliminate those suspect phthalates in such materials. In 2009, the US passed a law outlawing specific phthalates in children’s items. And because polymer clay is considered a toy, the formulation was changed and those suspect phthalate esters were no longer the plasticizer used. Several companies, such as FIMO, switched to other plasticizers well before this date.
Be aware that much of the scary information on the internet about the safety of polymer clay, such as this 2002 article written by a Vermont lobbyist organization, are outdated and refer to phthalates which are no longer used.
Many major brands of polymer clay now use a citrate based plasticizer. It is non-toxic, biodegradable, and safe to use in children’s toys, medical products, and any sort of PVC.
Baking Polymer Clay Safely
Of course, discussions of the toxicity of polymer clay always bring up the question of using a clay-dedicated polymer clay oven for baking. This is absolutely and unequivocally unnecessary. Please take a moment to read this safety information provided by Polyform, the makers of Sculpey and Premo. You’ll see that polymer clay does not release toxic fumes and does not create a residue in your oven when baked as directed. Or even when baked a little hotter than directed. (In fact, it’s well-known among pros that baking 10-20 degrees hotter makes the clay stronger, as does baking longer.) When polymer clay burns, however, it does release hydrogen chloride gas, which is caustic and will burn your lungs (but is not exactly toxic). But polymer clay doesn’t burn until it reaches temperatures near 350°F (175°C). So if your oven is accurate, this will not be a concern for you.
For more information on baking polymer clay, including how to get the best results, how to minimize any smells, and how to prevent browning and color change, refer to the articles that I’ve written on Baking Polymer Clay.
Many people find that the smells from baking polymer clay are unpleasant and some sensitive people might get headaches. If this is a concern for you, then by all means put your clay oven in the garage or porch. And cover your project during baking, taking the pan outside to open it up. But be assured that baking polymer clay does not produce toxic fumes.
Polymer Clay Safety Risks
Polymer clay is a plastic, and as such isn’t a whole lot different from any other plastic we use in our lives. It is PVC, the very same plastic that is used in our water pipes. But even though polymer clay is tested and certified to be non-toxic, there will always be the question, what if? What if “they” haven’t discovered yet that one of its components will cause problems years down the line? What if the plasticizers are more toxic than “they” know? Well, you can’t know. Not for sure. But that’s true for everything. You have to be rational and logical and not give into scary rumors and myths you might read. Find out the information that you can. Fear has no place here. And take reasonable precautions with your body’s safety, as you hopefully do every day in your life, whether you’re working with polymer clay or not. Regardless of your chosen hobby, you should be using good ventilation, appropriate protection (gloves or mask), and wash your hands afterward. It’s part of taking care of your body and being healthy. But you have to be logical about it. It’s just plain silly to freak out about “polymer clay contamination” and then ignore the many, many other plastics, industrial adhesives, carpets, and petroleum product outgassing that we encounter each day.
I suppose I could write a philosophical piece here about the risks we take in life. All plastic is nasty stuff, and it probably does cause issues for our bodies. But then so do food-borne illnesses and the dangers of improper food storage. Is it better to store milk in a plastic jug (plasticizers), a paper carton (dioxin), or a glass bottle which might not have been adequately sterilized? We are surrounded with dangers in life, both by chemicals and by things that happen to us. We do what we can to minimize the risks that we can control. We don’t smoke, we eat organic produce, and we avoid GMO’s. But we use cell phones and breathe exhaust and get into our cars which are filled with plastic. Some risk is unavoidable. But you have to evaluate the relative importance of these risks. And from what I can tell, working with polymer clay isn’t a very big monster on this list of risks. Now pardon me while I go get a snack. It’s a Diet Coke from a plastic bottle and some pesticide-laden grapes. (Gee…and we’re worried about a little polymer clay?)
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