Southern District Judge Alvin Hellerstein refused Tuesday to dismiss more than 3,000 lawsuits against New York City, the Port Authority of New York and New Jersey, and contractors who cleared Ground Zero that were brought by emergency workers who claimed respiratory damage and other illnesses from the cleanup after Sept. 11, 2001.

But Hellerstein said it was too early in the litigation to determine whether the defendants are entitled to immunity under the New York State Defense Emergency Act (SDEA) or other immunity doctrines, including one claim that the federal government supervised key elements of health and safety conditions at the site and the Fresh Kills landfill.