A 16--year old boy set himself on fire at a suburban Denver high school on monday in an apparent suicide attempt that left him critically injured, the boy didn't make any threats before starting the fire in the cafeteria at standley lake high school at about 7;15 a.m., A custodian was able to use a fire extinguisher to put out the blaze before it could spread, several other students were in the cafeteria at the time, but none were injured.