MORENO VALLEY, Calif. -

A 30-year-old man burned in a Moreno Valley explosion authorities say was caused by marijuana refining was facing possible drug charges Friday.

   The blast happened at about 12:50 a.m. Thursday at the Walker Terrace Apartments in the 13200 block of Heacock Street, Riverside County sheriff's Sgt. Brian Holmes said.

   Deputies arriving on scene found the man outside an apartment, suffering from burn wounds over his body, Holmes said.

   The man was taken to a hospital for treatment and investigators subsequently learned that his apartment allegedly contained a lab used to extract concentrated oil from marijuana, he said.

   Investigators with the sheriff's Drug Endangered Children unit responded and found that four children were at risk due to the lab and explosion, Holmes said without detailing what happened to the youths.

   Because of the severity of his injuries, the man was not arrested, but the case will be presented to the county prosecutor for further review, Holmes said.