Complex sentence: Curtis breaks the news to Prescott that the East Coast plant has been compromised and sabotaged by one of its own chemists (George Pembroke) who stole half of the formula, now identified as working for the Nazis under the name of Karl Schmidt.
Split into simpler sentences: Curtis breaks the news to Prescott that the East Coast plant has been compromised and sabotaged by one of its own chemists. The chemist abandoned the plant with half of the formula, and has now been identified as working for the Nazis under the name of Karl Schmidt.