Cmdr. Mark Riddle, an environmental health staff member from the Department of Sonsonate, El Salvador Ministry of Health; and Ma

110718-F-ET173-083 
AYACACHAPA, El Salvador (July 18, 2011) Cmdr. Mark Riddle, left, from Truckee, Calif., a preventative medicine physician; an environmental health staff member from the Department of Sonsonate, El Salvador Ministry of Health; and Max Gyllenskog, from Smithfield, Utah, an environmental health scientist and volunteer embarked aboard the Military Sealift Command hospital ship USNS Comfort (T-AH 20), conduct a site survey of a landfill in Ayacachapa, El Salvador, during Continuing Promise 2011. Continuing Promise is a five-month humanitarian assistance mission to the Caribbean, Central and South America. (U.S. Air Force photo by Staff Sgt. Alesia Goosic/Released)

110718-F-ET173-083 
 AYACACHAPA, El Salvador (July 18, 2011) Cmdr. Mark Riddle, left, from Truckee, Calif., a preventative medicine physician; an environmental health staff member from the Department of Sonsonate, El Salvador Ministry of Health; and Max Gyllenskog, from Smithfield, Utah, an environmental health scientist and volunteer embarked aboard the Military Sealift Command hospital ship USNS Comfort (T-AH 20), conduct a site survey of a landfill in Ayacachapa, El Salvador, during Continuing Promise 2011. Continuing Promise is a five-month humanitarian assistance mission to the Caribbean, Central and South America. (U.S. Air Force photo by Staff Sgt. Alesia Goosic/Released)