Complex sentence: A hot spot of fallout from the Trinity explosion had contaminated the river water that the paper mill in Indiana used to manufacture the cardboard pulp from corn husks, aware of the gravity of his discovery, Dr. Webb kept this secret until 1949.
Split into simpler sentences: A hot spot of fallout from the Trinity explosion had contaminated the river water that the paper mill in Indiana used to manufacture the cardboard pulp from corn husks. Aware of the gravity of his discovery, Dr. Webb kept this secret until 1949.