Because encaustic does not require solvents, it is a relatively safe medium to work in. The four safety concerns for encaustic are:
With adequate ventilation and proper working temperatures encaustic is non-toxic. Working next to a window exhaust fan and having a source of fresh air coming in from another part of the studio gets rid of fumes adequately. It is important to create cross-ventilation in your workspace, because wax fumes can be irritants, causing headaches and coughing. We recommend using a thermometer and working within a safe temperature of 180-200°F. Warning signs that your wax is too hot include an acrid odor and smoking.
Heating tools and hot wax can cause burns to the skin. Wear an apron to protect yourself from spills. If you do not have a sink, keep a bucket of cool water in your studio. If you are burnt, bring the temperature of the burn down immediately by immersing the burn in cool (not cold) water. Do not peel wax off your skin. It will seal the burn from oxygen, and peeling it can tear the skin. Keep the burn immersed for at least half an hour, unless you have a burn kit, in which case apply the dressing once the burn has cooled down in the water. If the burn is serious, seek medical help.
Paint in general, and toxic pigments specifically, should not be ingested. Encaustic pigments do not get absorbed into the skin, but we recommend you clean your hands before eating and do not eat or drink near your work area. Barrier creams help make paint easier to wash off your hands. Commercially made encaustic should have an ASTM labeling for toxicity. The ASTM labeling ensures that the specific pigment is stable and will not decompose or volatilize at working temperatures.
All solvents are liquid organic chemicals and are toxic. Heating solvents is dangerous and can make them even more toxic. Avoid using solvents of any kind with encaustic.