In an attempt to treat thousands more individuals with health problems stemming from the attacks of September 11, 2001, the city is undertaking a major expansion of its World Trade Center Environmental Health Center at Bellevue Hospital.

The city plans to open two new sites, at Gouverneur Healthcare Services in Manhattan and Elmhurst Hospital Center in Queens, at a cost of $33 million. City officials said yesterday that they hope to enroll 20,000 individuals for treatment over the next five years. To coincide with the expansion plan, the fire department yesterday released a 64-page report on the physical and psychological effects of the attacks on rescue workers. Based on a six-year assessment of 14,200 firefighters and Emergency Medical Service technicians, the report found that more than 79% of those who responded to the attacks experienced at least one lower respiratory symptom.

The report also found that the number of retiring firefighters and fire officials who collected disability pensions for lung problems after 2001 increased to an average of 146 individuals a year compared to 49 a year before the attacks.

“These statistics are heartbreaking,” Mayor Bloomberg said, reiterating his support for increased federal funding to treat illnesses related to the attacks.

In a statement, Rep. Jerrold Nadler praised the mayor’s support for the James Zadroga 9/11 Health and Compensation Act, which he introduced in Congress last week with Reps. Carolyn Maloney and Vito Fossella. The bill would fund the treatment of health issues related to the attacks and would reopen the Victim Compensation Fund.

“Whether you were caught in the plume, cleaned up poisonous indoor dust, or were exposed to contamination in your home or workplace — if you were exposed to toxins from the World Trade Center, you should have access to quality care,” he said.