Sodium acetate, frequently known as hot ice, is often used as a hand, body or foot warmer in cold weather. When in a liquid state, if a metal disc is clicked, the solution becomes solid, and in a matter of seconds releases a great deal of heat in an exothermic reaction. The bag is then boiled until it turns into a liquid, storing the heat until it is needed later.
Sodium acetate, when consumed in large quantities, can cause abdominal pain, nausea and vomiting in extreme cases. While you are not in danger of death, call Poison Control and drink several cups of water to dilute the solution.
Skin or Eye Contact
When handling sodium acetate not in a secure container, always wear gloves, goggles and gear that covers the skin. If your skin comes in contact with the substance, it may become red and irritated. If this happens, immediately wash the skin with water for 15 minutes, removing any clothing that may have been contaminated. Wash all clothing thoroughly before putting it back on. If you sustain eye contact, immediately flush the eye with clean cold water for at least 15 minutes. Make sure you get water underneath your upper and lower eyelids. If your eye continues to be irritated, seek medical attention.
The sodium acetate reaction produces a prodigious amount of heat which can easily burn skin. Make sure you have a thick layer of cloth between your skin and the hot ice. Do not use the pack as a hand or a foot warmer;, rather put it in a chest pocket and use it to keep your core temperature up. If you get burned, follow standard procedures for dealing with it. If you have access to vitamin E or aloe, immediately apply to the burnt area. Always use hot ice with natural fibers. Other fibers can melt and cause far more significant burns.
In high altitudes there have been instances where the sodium acetate reaction has caused fires when in dry conditions and when in contact with combustible material. Always be observant when using hot ice, whether in dry or wet conditions. Layer the sodium acetate packet in cloth so that it is in an oxygen-deprived environment.