Ceramic tile is a natural material, and some types of tile are made from recycled glass (including the products listed below). When buying tile (especially imported tile), just be careful not to buy tiles with lead-based or radioactive (often cobalt blue or burnt orange) glazes. Also, use non-toxic adhesives, mortars, and grouts for installing the tile.
Purchase a heater with a guard around the heating element. A wire grill or other protection is essential to keep fingers or fabrics from touching the hot element. Portable electric heaters that heat by circulating oil or water, however, usually have lower surface temperatures and may not need guards.