Doctors and government investigators told a House subcommittee it could take decades to detect all the health woes stemming from the Sept. 11, 2001, terrorist attack and subsequent cleanup around New York's World Trade Center.
The two most common conditions found so far are lung damage and post-traumatic stress disorder.
The government is currently funding six separate health screening programs to monitor those who came into contact with dust from ground zero in New York. Each program is run separately; none is funded beyond 2009.
Dr. Stephen Levin, who heads Mount Sinai Medical Center's Sept. 11 health screening program, said that timeframe would not catch any cancers caused as a result of exposure.
"In this witches' brew of airborne materials found at and near ground zero were a number of carcinogens, including asbestos and the ... cancer-causing chemicals in tobacco smoke," said Levin.
The doctor said about half of the first responders reporting symptoms 10 months after the attacks suffered from at least one lung problem, like wheezing, coughing, or shortness of breath. An equally high percentage was still showing signs of psychological distress, Levin said.
Rep. Christopher Shays, R-Conn., chairman of the House Government Reform Committee's national security panel, compared the health problems to soldiers who smoked heavily during wartime, but didn't show signs of lung cancer until decades later.
"Those who labored and lived near ground zero fought to survive against a subtle, prolonged assault on their bodies and minds. Many are still fighting," said Shays.
Two New York Democrats derided the government efforts to date as too little.
Rep. Jerrold Nadler, whose district includes the World Trade Center site, accused federal agencies of not doing enough to test and clean interior spaces in lower Manhattan.
"I believe residents are slowly being poisoned today," Nadler said.
The Department of Health and Human Services coordinates much of the current health screening, but doesn't have even a basic estimate of the number of victims, said Rep. Carolyn Maloney, D-N.Y.
"How many people are still suffering or still sick?" she asked.
"I'm not sure anyone could give you an exact figure," answered Dr. John Howard, director of the National Institute for Occupational Safety and Health.
Howard said new estimates expected later this week could provide a better sense of the scope of Sept. 11-related health problems.
He also said there was scientific value in using multiple programs to study the health affects from different perspectives.