FIRE UNITS WERE RESPONDING TO A REPORTED MVA ON ROUTE 287 INVOLVING A TRACTOR TRAILER AND A PASSENGER VEHICLE.  THE PASSENGER VEHICLE STRUCK THE SIDE OF THE TRACTOR AND RUPTURED THE FUEL TANK.  HAZMAT WAS SPECIAL CALLED.  WHILE HEADING TO THIS CALL, FIRE UNITS ENCOUNTERED A THREE VEHICLE MVA AT THE OFF RAMP BY STELTON ROAD.  SIX PERSONS WERE INJURED AND ONE WAS TRAPPED.  CHIEF MOCHARSKI WAS IN COMMAND AS ENGINE 4 AND RESCUE 1 WERE DIVERTED TO THE ALARM WITH ENGINE 4 STRETCHING IN WITH AN ATTACK LINE AND RESCUE 1 SETTING UP FOR EXTRICATION.  FIRE FIGHTERS ATTENDED TO THE INJURED AND HANDED OFF ALL PATIENTS TO ARRIVING EMS UNITS FOR TRANSPORT.