Complex sentence: For example, in the September 11,2001 attacks on the World Trade Center, some of the fire exits inside the building were inaccessible, while others were locked and in the Stardust Disaster the fire exits were locked and most windows barred shut.
Split into simpler sentences: For example, in the September 11,2001 attacks on the World Trade Center, some of the fire exits inside the building were inaccessible, while others were locked. In the Stardust Disaster the fire exits were locked and most windows barred shut.