MICHIGAN CITY, Ind. (AP) _ Scientists and engineers are using radar to determine the safety of a northern Indiana sand dune that collapsed onto a 6-year-old Illinois boy, burying him under 11 feet of sand.
 
  Environmental Protection Agency spokesman Francisco Arcaute says the device employed Monday in the inspection at the Indiana Dunes National Lakeshore is usually used to search underground at hazard waste sites. 
 
  Park ranger Bruce Rowe says the crew could be at the site for at least two days and that Mount Baldy will remain closed until the National Park Service considers the dune safe.
 
  Emergency workers freed Nathan Woessner, of Sterling, Ill., after he disappeared under the sand for more than three hours July 12. He then spent two weeks in a medically induced coma but is now home.