ROUGH CUT (NO REPORTER NARRATION)<br/> <br />STORY: Four people were injured in Sao Paulo Monday after a dramatic car explosion during a protest at a road block.<br/> <br />The protesters overturned the car onto a small fire at a roadblock during a protest over rent allowances. The car exploded into a ball of fire.<br/> <br />Fire-fighters said that the vehicle's bio-fuel system ignited, sending debris over 300 meters into the air.
