Refractory plaster has silica added to the plaster to allow the mould to withstand the heat of a firing. The product and instructions carry a warning to wear a face mask while mixing. Remember, that also applies to everyone in the work area. Buddies, helpers and the photographer (for your super YouTube show of this procedure) need to wear masks as well.
Keep all pets out of the workspace until you have wet mopped and wiped down all surfaces.
If working outside, try to avoid a windy day. Spread a drop cloth and do not sweep up any dried powder, use water to clean up.
Remember all precautions are to prevent airborne particles.
This information will show up again as part of future blogs, but it is important information that can bear repeating and so will be fine for practicing setting up tags while we are learning to change our format on this site!