As the first cases in a massive battle over illnesses linked to 9/11 near trial, an Associated Press investigation has found several of the initial 30 suits contain inconsistent or exaggerated claims about how the workers got sick or how much time they spent at ground zero.

A demolition worker who said he developed health problems after toiling for six months in the toxic ruins of the World Trade Center has actually been severely ill since the 1990s. In a previous medical malpractice case, he said he was so sick from 2000 to 2003 that he couldn’t work regularly. He never mentioned 9/11 during his testimony in that lawsuit.