Complex sentence: The attack killed between 3,200 and 5,000 people, and injured around 7,000 to 10,000 more, most of them civilians; thousands more died of complications, diseases, and birth defects in the years after the attack.
Split into simpler sentences: The attack killed between 3,200 and 5,000 people and injured 7,000 to 10,000 more, most of them civilians. Thousands more died of complications, diseases, and birth defects in the years after the attack.