The 'safe' lime is hydrated lime or ground limestone.
Edited by LynneP - 11/2/08 at 6:33am
The dangerous lime is 'quicklime' or mason's lime.
Agricultural lime is usually limestone, but some farmers use quicklime for specific trouble spots.
Be *very* careful when purchasing, as both are often available at the same source.
We once had a teacher at our school purchase the wrong kind to lime a playing field, with the result that kinds got burned and the grass was destoyed. The wrong lime can't we wahed off, it heats up in water. Causes respiratory distress in addition to burns.
If you are worried about choosing, select a product like Stall Dri or Stable Boy, labelled for animal use.