I had this happen to me this year - first time in 24 years of hunting. They were the thicker steps and had been in an old oak for many years. I believe it was the pressure the growing trunk exerted on the step that made it weak. Thankfully, it was the first step from the ground. It broke under my foot and I fell to the ground hitting my gut on another step on the way down. Luckily, it hit my right side between my last rib and my waste. Plus, I had many layers of clothes on which kept the impact minimal and only gave me a nasty baseball size bruise rather than gutting me or breaking a rib. Could have been way worse all the way around. Never dreamed that would happen. Now I'm concerned about all my other stands that have been in trees for 10+ years with screw in steps. I think I'm going to replace these steps with ladders.