What kind of precautions should I undertake to use epoxy-based paints?
DIY epoxy floor paints do not normally require respiratory protection during application (by brush or roller) as long as adequate ventilation is provided. These "off the shelf" products are designed for use by laypersons. What is "adequate"? Open all doors and windows, for basements or other areas with scant natural ventilation put a box fan or two in a door or window to pull fumes out and allow fresh air to be pulled in. If you are a particularly sensitive individual or if you intend to spray the coating, a full-face respirator with organic vapor cartridges is commonly recommended. Always follow manufacturers' instructions.

Commercial/industrial products are labeled and distributed as such and are not usually available for purchase by the average homeowner.