The powder in the Animal Tracking Explorer Kit from Mindware, marked “plaster of paris” is actually calcium hydroxide, (commonly named slack lime, pickling lime or hydrated lime) which poses a risk of skin and eye irritation to children using the product. Calcium hydroxide is a common ingredient in grout but also comes in many forms and is used for a great variety of things;

• A flocculant, in water and sewage treatment and improvement of acid soils
• An ingredient in whitewash, mortar, and plaster
• An alkali used as a lye substitute in no-lye hair relaxers
• A chemical depilatory agent found in Nair
• An ingredient in baby formula milk

Of course I will point out that I am not a scientist and have no authority on the subject, so as a concerned parent I have only questions and no real answers. I assume the form of calcium hydroxide they’re talking about is the commonly found in a number of masonry mixes which I can tell you from experience, will over a time give you a noticeable lime burn. It is also very bad to inhale the dust.

The bottom line is heed this recall and either throw the product away or follow the link for the recall and get your money back.

And yes if you were wondering, the kit is manufactured in China.

Sited Links:
Children’s Animal Tracking Explorer Kit Recalled
US Department of Health | Household Products Database
Wikipedia | Calcium Hydroxide