NEW YORK -- As the first cases in the battle over illnesses linked to the cleanup after 9/11 near trial, an Associated Press investigation has found that 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.

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

Attorneys for a police officer from northern New Jersey who died in 2006 claimed in a court filing that he spent nearly 300 days handling debris at ground zero, but his work records indicate that his actual time and duties related to 9/11 were far more limited. During the months the attorneys said the man worked at ground zero, he was recording full-time shifts in Cresskill, N.J.

Another police officer, who was listed by her attorneys as having lung cancer, doesn't have cancer. Her actual illness involves something akin to chronic asthma. She insists her attorneys were mistaken.

The three cases are among the 30 plaintiffs whose suits are being considered for trial in May over new York City's culpability for chronic illnesses caused by exposure to contaminated dust in the months after the Sept. 11, 2001, terrorist attack.

More than 9,000 legal claims were filed against New York City, and about 60 have gotten close scrutiny by the court. U.S. District Judge Alvin Hellerstein, who is overseeing the case, has said he hopes to whittle the initial trials, which will serve as a road map to settlements for the many other claims, to 12.

More than $1 billion in damages is at stake.