Data gathered on more than 27,000 police officers, firefighters, and construction and municipal workers revealed that many suffer continuing ill-health.
A separate study showed that firefighters exposed to toxic dust and chemicals in the aftermath of the outrage had a 19 per cent increased risk of cancer.
Almost 3,000 people died when Islamic extremists flew two passenger jets into the World Trade Centre twin towers on 11 September 2001. Among them were 343 firefighters.
The collapsing buildings released choking clouds of dust and debris containing toxic substances, including known cancer chemicals.
More than 50,000 rescue and recovery workers are estimated to have provided assistance after the attacks.
One of a series of studies published in the Lancet medical journal looked at how many of them continued to suffer from a range of health problems.
It showed that the risk of asthma, sinusitis and gastro-oesophageal reflux disease – a condition marked by chronic heartburn – was greatest in workers with the highest levels of exposure.
Overall, almost a tenth of rescue and recovery workers had been diagnosed with all three conditions while 18 per cent suffered from two of the disorders.