Human exposure to the toxins has previously been associated with lung diseases such as asthma, bronchitis, and COPD.
Christopher Philip Ahn had fought to keep the court documents sealed, citing North Korea's history of hunting down opponents.
"I thought he was going to rape me," a sports reporter said about an alleged encounter with Walton at a hotel.
The mother of 15-year-old Nigel Shelby said he had been bullied over his sexuality.
Tuesday's death is the second fatal fall inside the park this year, and the third in the Grand Canyon area.