Lawyers for New York City claim 30 percent of those suing in federal court claiming ground zero-related illnesses don't have serious health problems.

The city is fending off claims of approximately 10,800 plaintiffs, who claim to suffer from one or more of 387 different types of injuries. The claims are filed in federal court in Manhattan, where Judge Alvin Hellerstein is overseeing the cases. About half of the claims were filed by city workers, such as NYPD and FDNY personnel.

In a letter to Judge Hellerstein last month, a white-shoe firm hired by the city contended that their review of the pending claims show about 30 percent of the people seeking compensation allege "only nominal injuries."

The city says those are cases where a specific injury is not diagnosed, but instead only a symptom described, such as runny nose or sleep problems.

"This is not to suggest that the remaining 70 percent of plaintiffs are seriously injured," the lawyers wrote to the judge. "To the contrary, diagnosable injuries such as sinusitis and acid reflux are not necessarily serious."

More than 300 of the claims, or about 3 percent of the total, "do not claim any past or current physical injury," the lawyers contend.

A call to one of the lawyers for the workers was not immediately returned, but in a separate letter sent to the judge last month, the workers' advocates suggested the two sides could work together to categorize claims by their severity.

The city's letter was first reported in Wednesday's editions of the New York Times.

The case is part of a running argument over how many people were actually sickened by their exposure to toxic debris at dust at the World Trade Center site, and years-old disputes about who should pay for such illnesses.

Lawyers for the city contend that serious illnesses that can be medically documented and tied to ground zero exposure should be paid for by the federal government. But the federal government created a $1 billion captive insurance fund, administered by the city, to handle such claims. Lawyers for the workers say the city should stop fighting the claims and start paying them.