after that toxic train wreck in ohio, or face a massive fine. norfolk southern s corporate greed is absolutely unacceptable. norah: alex murdaugh s son takes the stand. the emotional testimony about the murders of his mom and brother. when you got there, did you see your dad? yes, sir. he was destroyed. he was heartbroken. norah: an explosion outside miami kills at least two people. the consumer alert for parents. reporter: 145,000 cans of baby formula are being voluntarily recalled over contamination fears. reporter: people in new orleans and beyond are celebrating mardi gras starting today. we are having a blast out here! norah: good evening to our viewers in the west, and thank you for joining us on this tuesdayhtig n. tonight, cbs news goes in-depth in part two of our series on americans being exposed to chemicals in our food, and what is being done about it. plus, how former president jimmy carter s hometown of plains, georgia, celeb