Safety on polymer clay

People new to polymer clay are often confused about its level of safety. This is understandable, because there do seem to be pieces of conflicting evidence, or at least conflicting points of view.

The general consensus is that polymer clay is non-toxic, but that it is advisable to take certain precautions, "just in case". However, take all of these precautions with a grain of salt. Honestly, chances are that the Double Whopper with cheese you ate for lunch is more of a health risk than polymer clay. Practice safe claying, but don't let safety concerns take all the fun out of clay, and certainly don't let fear keep you from giving it a try.

Here's a list of guidelines for the safest use of polymer clay:

1. Don't eat it.

Though polymer clay is certified "to contain no materials in sufficient quantities to be toxic or injurious to humans, including children, or to cause acute or chronic health problems, even if ingested," it is wise to keep it out of the reach of young children or pets who might try to eat it.

For the same reason, it is important to carefully wash your hands after handling raw clay. And you should never let raw clay come into contact with food or drink.

2. Don't eat off of it, either.

Dishes made from polymer clay are not suitable for eating from, and cured polymer clay should not come into contact with food, in general. Cured polymer clay is too porous to be sufficiently cleaned after contact with food. These pores can act as a breeding ground for bacteria and other nasty things that you wouldn't want to mingle with your next meal off of that polymer clay plate. So just don't do it. Reserve your polymer clay pottery for display or other uses that don't involve food.

3. Use clay-dedicated tools.

There are many tools in our kitchens that work wonderfully with polymer clay, and it is very temping to "borrow" from your kitchen. It's fine to use a kitchen tool with clay, but once you've used it with clay, it should be dedicated for use with clay only. So if you use that meat mallet to texturize your clay, don't use it to pound the steak for supper. Pasta machines, food processors, knives, graters, peelers, and so on-- if you've used it with clay, it's gotta stay… out of the kitchen, that is.

Note:  Tools made of metal or glass and with no nooks and crannies for clay to hide in can probably be cleaned well enough to go back to food use, but most clayers agree that it's best not to tempt fate. Besides, it's just a lot easier to have one tool you leave in the kitchen and another for your box of clay tools.

4. Don't let it burn (obviously).

As long as clay is baked at the correct temperature, there are no unusual "fumes" to worry about. You may notice a slight smell, but this is normal. If it bothers you, or if you do a lot of curing, you may want to cure out of doors or use a vented oven. If nothing else, you can open windows while you bake.

It is when clay is cured at excessive temperatures that it burns and releases those "toxic fumes" you've probably heard of. These fumes are hydrochloride gas (or "hydrochloric acid gas"), and while that sounds scary--  and they're certainly not something you want to produce when curing clay--  the fact is that it has no chronic effect. The gas can irritate mucus membranes, causing stinging eyes, nose, and throat, but once you've turned off the oven and cleared the area of people and pets (until the gases have dissipated), you should begin to feel better and have no lasting ill-effects.

And if you are careful, you should never have to worry about "toxic fumes" at all.

1. To avoid burning clay, it is crucial that you get an oven thermometer. The thermostats of most home ovens and toaster ovens are "off"-some by fifty degrees (Fahrenheit) or more. As anyone who bakes can tell you, no two ovens are exactly the same, so it is important that you know how your own oven(s) work. Carefully gauge the temperature to avoid burnt clay.
2. If your oven has an exposed heating element, try to keep your clay away from it. When the heating element comes on, the temperature inside the oven can spike-especially right next to the element.
3. Be sure to notice if any cured clay has been left in the oven or fallen to the bottom of the oven. If it has, remove it immediately, before you forget that it's there. This is especially important if you use your oven for other things and will be baking at higher temperatures, later on.

Common Concerns

Should I use a special "clay-only" oven?
Some people worry about curing clay in the same oven that they use for baking food. There doesn't seem to be any reason for concern. If you regularly clean your oven, it should be fine to cure clay and bake food in the same oven-- though probably it's best not to do both at the same time.

However, if you frequently cure clay in an oven, it may have a "baking-clay" smell whenever you heat it, even if there's a casserole inside instead of more clay.  If this bothers you, or if you simply wish to take extra precautions, you may want to purchase a clay-dedicated oven or seal your clay projects while you cure them. If you use a clay-dedicated lidded dish or simply cover the pan/cookie sheet with aluminum foil (which you can "seal" by crimping under the edges of the cookie sheet), you should greatly reduce the smell of baking clay.
Do I need to wear gloves?
Most people notice no adverse effect from touching clay with bare hands. Highly pigmented clays in some brands may temporarily tint your skin, but that's usually easily washed away. There's no safety-related reason to wear gloves when you work with clay unless you've noticed that your skin reacts adversely to it. Some people seem to be allergic to something in the clay. If you do develop a rash, you may wish to contact a physician for personalized advice, but wearing gloves will probably solve the problem.

As for what type of gloves to wear, most people wear cheap latex or vinyl gloves, but some prefer to pay a little more for nitrile gloves. Some of these people are allergic to latex; others worry that prolonged contact with latex might lead them to develop a latex allergy. Again, unless you have an allergic reaction to the clay itself (which is unlikely), there's no reason why you have to wear gloves at all, though many do find that wearing gloves cuts down on fingerprints in the clay.
Whether or not you wear gloves, remain conscious of what you do with your hands when you've been handling polymer clay.  Avoid touching your eyes and face.  As much as possible, try not to touch anything that you wouldn't want "contaminated" with clay (nice furniture, fabrics, electronics, etc.) until you've had a chance to remove your gloves and/or wash your hands. 

http://www.polymerclayweb.com/AboutPolymerClay/TheBasics/SafetyIssues.aspx