authorities, their focus is trying to get the search and rescue teams to this building so that they can get access to that one worker that is still missing. that is their focus, but they also say that osha is on scene ready to investigate and fred, i want to leave you with this picture. this is from wvue. this is of the family of that missi inin ining worker. they told our affiliate they are not leaving this site until their loved one is found. >> goodness. so sad. we are all praying for the best possible outcome and hopefully the search and rescue teams will be able to deliver some hopeful news. rosa flores, thank you so much. coming up, the stage is is set for a big night in politics. the fourth democratic presidential debate happening in just two days. right here on cnn. how are the candidates preparing? in what could be a make or break moment for their campaigns. that and more right after this.