Oceanside

An explosion in a chemical plant Thursday afternoon shattered its windows and prompted the evacuation of nearby buildings, the Oceanside fire marshal reported.

The explosion, which occurred at 4:09 p.m. in the J.C. Schumacher Chemical Plant at 580 Airport Road, apparently was caused by an experiment conducted by one of the plant’s technicians, Battalion Chief Ted Wackerman said. He said the explosion did not cause any flames.

Estaban Diaz, 24, a chemical technician, was conducting an experiment in a contained area--involving the chemicals boron triboromide and dolomite when the explosion occurred, Wackerman said.

Diaz, who suffered facial burns, was taken to UC San Diego Medical Center and was reported in critical condition, Wackerman said. He said six others voluntarily went to Tri-City Hospital for observation, but were released shortly thereafter.

Three buildings east of the plant were evacuated immediately after the explosion by safety officers of the chemical plant, Wackerman said.

He said officials were concerned initially about a cloud released by the explosion, but said such fears subsided when air samples taken at 4:20 p.m. showed no abnormal readings.

A spokesman for the company did not return phone calls Friday.