Among all the lasting images from Sept. 11, the sight of thick, pluming smoke enveloping the remnants of the World Trade Center towers, and then invading Lower Manhattan, is one that few will ever forget.

The sense of tragedy and chaos on that day was overwhelming. Most were too worried about the fate of loved ones and the utter destruction of what they had witnessed to focus on how the collapse of thousands of tons of concrete, steel, lead and a plethora of other toxic chemicals would impact the people who inhaled its dust while running from the site or attempting to unearth survivors.

These days, the health problems experienced by first responders, pedestrians and office workers who were caught in the dust on that day -- as well as in the days, weeks and months afterwards -- may be our most tangible connection to the tragedy.

Harmful, Particle-Filled Dust

Paul Lioy, the director of exposure science at Rutgers University and author of Dust: The Inside Story of its Role in the September 11 Aftermath, said the magnitude of dust that resulted from the collapse of the Twin Towers is one that had never been before.

The particle sizes are not what we normally see in the air every day -- these were very large, extremely large. We didn't even have a definition for the size, Lioy told ABC News.

Analyses of the dust showed that the substances in it included cement, calcium carbonate, glass fibers, gypsum, the highly carcinogenic compound asbestos as well as other toxic materials such as lead, mercury and cadmium. The dust reportedly contained more than 2,500 contaminants, many of which have been shown to trigger kidney, heart, liver and nervous system deterioration.

As a result, many rescue workers and bystanders who were exposed to the toxic dust have developed serious respiratory ailments and cancers that have been linked with the exposure to toxins from the Ground Zero site.

A 2010 study of nearly 13,000 rescue workers published by the Office of Medical Affairs at the New York City Fire Department found that a significant number of those who suffered acute lung damage after exposure to the World Trade Center dust had not recovered normal function in the years since Sept. 11.

We demonstrated dramatic decline in lung function, mostly in the first 6 months after 9/11, and these declines persisted with little or no meaningful recovery of lung function among FDNY rescue workers over the next six-and-a-half years, said Dr.  David Prezant, the senior author of the study.

Prezant noted that the medications prescribed to those affected eased symptoms but did not provide a cure to their chronic ailments. Thirty percent to 40 percent of workers reported persistent symptoms --such as difficulty breathing -- while about 1,000 of the study participants were on permanent respiratory disability.

It is hard to say how many rescue workers have died from illnesses related to the dust.  In 2009, the New York State Health Department had recorded 817 deaths of emergency workers, but there is no official tally, and even then the department said it could not confirm how many of those fatalities were directly linked to the site.

Compensation Act Has Gaps

In 2010, federal legislation was passed to provide health monitoring and financial aid to sick rescue workers. The bill, called the James Zadroga 9/11 Health and Compensation Act, was named after a deceased NYPD officer whose death was the first to be attributed to his exposure to toxic chemicals in the aftermath of the Sept. 11 attacks.

However, while the legislation covers a number of pulmonary diseases, it does not cover cancer. Lawmakers said that -- despite the amount of carcinogenic chemicals found in the dust and number of cancer-related deaths among rescue workers -- there was not enough medical evidence that the dust that resulted from the destroyed towers contributed to the disease.

In what is perhaps a tribute to the 10th anniversary of the calamity, some lawmakers have decided to fight for the inclusion of cancer onto the list of covered diseases. U.S. Reps. Carolyn Maloney, D-N.Y., Jerrold Nadler, D-N.Y., and Peter King, R-N.Y., announced on Wednesday that they are filing a petition to request the change, a move that will likely be met with applause by those who braved through the dust on a day that is still fresh in the collective consciousness of the nation.