NEW YORK (AP) -- A man who died of lymphoma and lung disease more than seven years after he was exposed to toxic dust from the World Trade Center collapse was added to the Sept. 11 death toll, the New York City medical examiner said Friday.
Leon Heyward, 45, died Oct. 13 of lymphoma that was complicated by the lung disease sarcoidosis and the use of the chemotherapy drug cyclophosphamide, the medical examiner's office said.
Ellen Borakove, a spokeswoman for the medical examiner's office, said Heyward was near the twin towers when they collapsed. She did not say how long Heyward had been ill or whether he worked in the trade center.
His family could not immediately be reached Friday.
Deaths may be reclassified when "people die of disease that is caused by exposure to the dust that occurred in the time of the collapse," Borakove said.
Chief medical examiner Charles Hirsch listed Heyward's death as a homicide. The family did not formally request to add Heyward to the Sept. 11 death toll, Borakove said.
Hirsch last added the illness death of Felicia Dunn-Jones to the official toll in 2007 after her family made the request several times, but the judge has declined to make similar rulings in half a dozen other cases.
Dunn-Jones, a 42-year-old civil rights attorney, was caught in the dust cloud that enveloped lower Manhattan on the day of the attacks.
Medical experts researching the severity of post-Sept. 11 illness have said the risk of exposure was greatest on the day of the attacks, although thousands of people have said they developed respiratory illness, cancer and other ailments from breathing in fumes during the nine-month cleanup.
Dunn-Jones developed a persistent cough shortly after Sept. 11 and died in February 2002.
Hirsch cited research that showed a link between sarcoidosis and ground zero dust exposure and said that Dunn-Jones' exposure contributed to her disease.
Later in 2007, however, Hirsch reversed a New Jersey medical examiner's decision that a retired city police detective's death was caused by exposure to toxic dust. Hirsch ruled that James Zadroga's improper use of prescription drugs exacerbated his lung disease.
The 34-year-old Zadroga's name was later added to the New York Police Department's memorial wall as an official Sept. 11 victim.
Many victims' family members have said they wanted symbolic recognition that their loved ones' deaths were caused by the terrorist attack. Researchers studying Sept. 11-related illness also have watched the cases closely, as they establish direct links between trade center exposure.
The death toll from the trade center attacks now stands at 2,752.