"In 1954, Paul suffered a series of injuries, including a hip injury from pulling a 3500lb safe that had accidentally frozen to the ground. He also broke his wrist during a world record attempt in Indianapolis, and a short time later, suffered multiple broken ribs from a car accident. Paul rebuilt the cast on his arm using steel rods and supports, so as not to hinder his training." How Paul Anderson Became One of History’s Strongest Humans
By Brooke Siem
The safe that was claimed to weigh 3,500 lbs was found when his daughter had it weighed , to weigh about 1,200 lbs less, so in addition to the backlift entry being removed from Guinness due to 'lack of witnesses', the total weight was also much less than claimed.