A National Academies of Sciences, Engineering and Medicine panel has launched a study on the respiratory effects of burn pits and other pollution encountered by U.S. troops in the Middle East and Afghanistan. The planned 21-month review marks the second time a National Academies committee has explored the subject: In 2011, a group of physicians and scientists, under what was known then as the Institute of Medicine, concluded there was insufficient evidence to link troops' illnesses to exposure to burn pit smoke at Joint Base Balad in Iraq. The new committee, which includes just one member from the 2011 group, will review all available scientific and medical research on burn pits and airborne hazards and related illnesses. It will then evaluate and summarize them and make recommendations as warranted to the Department of Veterans Affairs, which requested the study. Read more about the panel on Military.com.