Lime is used to sweeten, or reduce the acidity of, the soil. The details of a given lime product's manufacturing determine whether it presents a poison hazard to your pets and livestock.
Powdered limestone rock, also known as agricultural lime, isn't considered toxic.
Heating lime produces the more reactive quick lime (burnt lime). It can irritate the skin, so keep it out of the reach of pets and small children.
Also knows as lime fertiliser or lime nitrogen, calcium cyanamide irritates the skin, eyes and respiratory tract, is toxic to humans and animals, and has demonstrated moderate to high acute toxicity from oral and dermal exposure in test animals.
To prevent accidental poisoning, either store lime fertiliser off the floor where dogs can't get at it, or in dog-proof containers. Sweep up spills promptly.
Horses should be removed from pastures where lime fertiliser is being applied and not returned until at least 1/2 inch of rainfall has occurred to wash the substance off all leaf surfaces.