A New York City man who died of lymphoma and lung disease three months ago has been added to the Sept. 11 death toll because of his exposure to toxic dust.

The city medical examiner's office says that 45-year-old Leon Heyward's death was caused by his breathing in the dust cloud caused by the collapse of the World Trade Center towers.

The medical examiner says that Heyward died in a city hospital on Oct. 13 of lymphoma, complicated by the lung disease sarcoidosis.

M.E. spokesman Ellen Borakove says Heyward was near the towers when they collapsed and breathed in the toxic dust. She didn't know when he had become ill.

In 2007, the office added the name of a woman who died five months after the 2001 attacks to the death toll because of her exposure to toxic dust.