It is kind of tough. I guess we will leave it without colour differentiation, but I had hoped to find a solution, to indicate the hazard for visitors who would have a vision impairment.
Thank you for your reply, it is a really good suggestion. I wonder if there is a road crush product in a substantially different color, because part of what we are trying to accomplish is to provide color and or texture contrast between the surface directly next to the fire, for someone who may have some visual impairment. Any thoughts on this?