Firemen work around the World Trade Center after both towers collapsed in New York, in this September 11, 2001 file photograph. Eleven years after the Sept. 11, 2001, attacks, New Yorkers will mark the anniversary on Tuesday against a backdrop of health concerns for emergency workers and a feud over financing that has stopped construction of the $1 billion Ground Zero museum. [Photo/Agencies]

Seven years ago, Riches was hospitalized with acute respiratory disease and fell into a 16-hour coma. He came out of the coma with stroke-like symptoms. "We can send men to the moon but we can't rebuild some buildings in more than 10 years?" he asked.

Some progress has been made by Larry Silverstein, the developer who owned the lease on the Twin Towers and is now building three office towers at the Ground Zero site, and the Port Authority. The National September 11 Memorial and Museum Foundation has also raised hundreds of millions in private and public funding for the overall project.

One step forward was last fall's opening of the September 11 Memorial at Ground Zero, twin reflecting pools in the footprints of the towers. More than four million people have visited.

Also, One World Trade Center, one of the tallest towers in the country, is near completion and expected to open in 2014.

Yet disagreements over costs have undermined the rebuilding and hurt public relations. Among the disputes, the foundation insists the Port Authority owes it $140 million, according to a source familiar with the financial issues. The Port Authority believes it is owed $300 million.

Feal, a demolitions expert who lost part of his leg doing post-9/11 recovery work, is more concerned about the health problems that persist. He said "2,751 lives were lost that day. That's sad, but they didn't suffer long. These first responders have been slowly dying for 11 years."