Many of the New Yorkers who rushed to Ground Zero to volunteer on Sept. 11, 2001, and now suffer from chronic health problems might not qualify for shares of a $2.8-billion federal compensation fund because they cannot prove they were at the attack site, writes The New York Times.

Unlike firefighters, police, city employees, and contractors, whose 9/11 actions are backed up by detailed records, scores of impromptu aid workers have only the sketchiest evidence of their presence in the so-called exposure zone in lower Manhattan.

The fund, created by Congress in 2010, requires claimants to provide orders, instructions, or confirmation of tasks they performed; medical records created during their time in the exposure zone; or two sworn statements from witnesses describing their aid work.