Complex sentence: Dr. J.H. Webb, a Kodak employee, studied the matter and concluded that the contamination must have come from a nuclear explosion somewhere in the U.S. discounting the possibility that little boy was responsible due to the timing of the events.
Split into simpler sentences: Dr. J.H. Webb, a Kodak employee, studied the matter and concluded that the contamination must have come from a nuclear explosion somewhere in the United States. He discounted the possibility that little boy was responsible due to the timing of the events.