Complex sentence: The disease was first recognised as being a result of radium paint ingestion after many female workers from various radium paint companies reported similar dental and mandibular pain and other symptoms in 1924, as a major cause of litigation against the United States Radium Corporation.
Split into simpler sentences: The disease was first recognised as being a result of radium paint ingestion after many female workers from various radium paint companies reported similar dental and mandibular pain and other symptoms in 1924. The condition was the major cause of litigation against the United States Radium Corporation.