Solomon said the group hopes to discover thecause of the flash fire in the remains of thechemical compounds which the students were workingwith.

The injured student is expected to resumeresearch on the Atmospheric Research Project soon.

"In order to calibrate the instrument [todetermine chlorine nitrate levels], we have tohave a source [of chlorine nitrate]," Solomonsaid. "It's a very unstable compound, and we haveto make it ourselves, he said. "It was during thissynthesis that the explosion occurred."

The students working with chlorine nitrate are"very aware of the danger," Solomon said.

Experiments performed with toxic materials arecarried out under the protection of a fume hood, adevice which carries harmful fumes out of thelaboratory by means of a chute and large ceilingfan.

Deputy Chief Reardon said that four fireengines, two ladder trucks, two rescue operationvehicles as well as Cambridge and Harvard policeresponded to the incident