When Judd says he heard about a firefighter in LA "who had a piece of rebar go through his brain" he is referring to Chimney in the 9-1-1 (2018) episode Next of Kin (2018). (9-1-1: Lone Star is a spin off of 9-1-1. )
The cave incident is based on the Utah Nutty Putty Cave fatal accident which directly caused the closure of the caves. In 2009, John Edward Jones mistook a narrow tunnel for a similar "birth canal" tunnel becoming stuck upside down. Rescue attempts failed and he died of cardiac arrest and the cave was sealed permanently with his body inside.