NATIONAL BRIEFING / NEW YORK

Researchers tracking Sept. 11 responders found many with lung problems years after exposure to the toxic dust caused by the World Trade Center’s collapse.

The study by the Mount Sinai Medical Center’s medical monitoring program examined more than 3,000 responders between 2004 and 2007, repeating exams conducted from mid-2002 to 2004.

Slightly more than 24% of the patients had abnormal lung function, the study found. In the earlier exams, about 28% had similar problems.

The study appears in today’s editions of Chest, a journal published by the American College of Chest Physicians.