In a review of nearly 18,000 workers and volunteers who climbed into the ruins of the Twin Towers in the hours and days following the attacks, researchers from the Icahn School of Medicine at Mount Sinai discovered many have begun to develop COPD after a previous asthma diagnosis. COPD is a chronic lung condition that causes breathing difficulties, coughing, and wheezing, which only gets worse over time.

Typically, the disease mainly impacts smokers, but doctors say people who work in environmentally hazardous conditions are also at risk. Previous studies have revealed that the dust cloud produced by the destruction of the Twin Towers contained numerous toxic chemicals that have led to diseases like cancer in the workers breathing in those particles.

"We know that emergency workers who arrived in the aftermath of the World Trade Center disaster face higher risks of airway diseases, such as asthma, chronic non-specific bronchitis and bronchiolitis, probably caused by the smoke and toxic dust that persisted in the air days and weeks after the attacks.