The 9/11 incident that brought down the World Trade Center will be forever remembered as an attack that left people in fear, panic, and turmoil. But what most people don't know is that for those who responded in ground zero are also left with a disease - asthma.

Those who responded at the World Trade Center attack suffer from asthma at more than twice the rate of the general U.S. population from exposure to toxic dust from the buildings' collapse, according to a study done by first author Hyun Kim, MD, epidemiologist and assistant professor of population health at the North Shore-LIJ Health System and the Hofstra North Shore-LIJ School of Medicine.

Looking at the data of all those who responded, the researchers found that 6.3% of the responders reported asthma symptoms and attacks, as opposed to the 3.7% of the U.S. general population that reported asthma symptoms or attack in the past 12 months. The study examines the 20,834 responders who received medical screening from July 2002 to December 2007 and comparing them with adult sample data from the year 2000.

Though the asthma rates of the general population remained stable, there were large increases in 12-month asthma rates among the responders from 2000 to 2005. When comparing the rates of asthma of the responders a year before 9/11, 2000 to 2005, the 12-month asthma rate increased by 40 times.

And in addition, when comparing 2002, a year after 9/11, to 2005, the 12-month asthma rate doubled among the responders.

In a report done by The Telegraph back in 2009, a follow-up study found that among the thousands of people that got caught up in the terrorist attack, 1 in 10 had been diagnosed with asthma five or six years after the incident.

While in a similar report done by CNN back in 2009, found that about 1 in 7, or 13.5% of adults who were at the site after the collapse were later found to have asthma.