Complex sentence: Dr. Roholm conducted laboratory studies, interviewed workers, and investigated incidents of fluoride pollution in several countries, such as the 1930 Meuse Valley fog where fluoride pollution from the nearby zinc factory killed 60 people and injured thousands.
Split into simpler sentences: Dr. Roholm conducted laboratory studies, interviewed workers, and investigated incidents of fluoride pollution in several countries. One such incident was known as the 1930 Meuse Valley fog where fluoride pollution from the nearby zinc factory killed 60 people and injured thousands.