A 12-year-old boy who was playing yesterday with a fireworks shell found on a field next to a Baltimore County elementary school suffered burns to his cheek and hand when the device detonated near his face, police said.

Authorities said they are investigating whether the child found unexploded ordnance left over from the county's professional display the night before next to Fullerton Elementary School.

Darren A. Moscerella, of the 100 Block of Lyndale Ave. in Fullerton, was in fair condition yesterday at Johns Hopkins Children's Center, according to a hospital spokeswoman.

"Children tend to experiment with fireworks, and unfortunately this young boy had to find out the hard way that it's not a good idea," said Baltimore County Police Cpl. Art Nilsen.

About 2 p.m., someone called 911 to report a loud explosion and a group of children running in the field at 4400 Fullerton Ave.

Three members of a police bomb squad found cardboard from a fireworks shell in the field near where Darren was hurt. It is unclear where the shell came from, police said.

More than a dozen police officers searched the field and went door-to-door through the neighborhood yesterday afternoon warning parents to keep their children away from unexploded fireworks.