The "World Trade Center cough": Ground Zero rescue workers say that have it; U.S. senators plan to find out if they do.

Sen. Hillary Rodham Clinton, D-N.Y., and Sen. Joseph Lieberman, D-Conn., will hold a hearing next month that will more thoroughly look at the destruction site's air quality and its effects on the many who have spent and are spending time there.

Clinton said Saturday that the Feb. 11 hearing in New York will be chaired by Lieberman, who serves with Clinton on the Senate Environment and Public Works committee.

Since the Sept. 11 terror attacks, workers at the trade center and neighborhood residents have developed respiratory problems, including the so-called "World Trade Center cough," along with various other symptoms including shortness of breath and wheezing.

But the long-term consequences of breathing the air rising from the debris are still under debate, with medical experts disagreeing on the seriousness of exposure to air that may contain possible carcinogens including asbestos and PCBs.

"Unfortunately, we do not really know what our firefighters, police officers, EMTs and others have been exposed to as a result of their courageous efforts at Ground Zero, but it is our responsibility to find those answers," Clinton said at a press conference in front of Engine 40, Ladder 35, a fire station where all 12 men on duty Sept. 11 were lost.

Clinton said she has discussed monitoring the health of rescue workers with officials of the Environmental Protection Agency and the United Firefighters' Association, which represents most city firefighters.

Dr. David Prezant, a Fire Department lung specialist who joined Clinton, said that of the 8,000 people examined so far, those who worked at Ground Zero in the first days after the attacks showed the most serious respiratory symptoms.

Overall, he said, some 25 percent of the 11,500 firefighters who spent time at the disaster site have some level of symptoms, either complaining about shortness of breath, weakness, coughs or stress- related problems.

Clinton helped appropriate $12 million for a study of the health impacts associated with Ground Zero, a joint project between the federal Centers for Disease Control and Prevention and city health officials.

The Associated Press contributed to this report.