Abstract: THE REFRACTOR LINING OF A BOILER HAD BEEN REPAIRED. TO GAIN ACCESS TO THE BOILER, THE WIRING FOR THE BURNER CONTROLS HAD BEEN DISCONNECTED AND THE MAIN GAS VALVE SHUT OFF. AFTER THE REPAIRS WERE COMPLETED THE WIRING WAS RECONNECT BY A MECHANIC. THE MECHANIC HAD COMPILED AN INCOMPLETE LIST OF THE CONNECTIONS. THE MAIN GAS VALVE WAS THEN OPENED. EMPLOYEE #1 WAS CALLED TO START THE BOILER. HE CLOSED THE BREAKERS, BUT NOTHING HAPPENED. HE CHANGED A FUSE AND ATTEMPTED ANOTHER START-UP. EMPLOYEE #1, ALONG WITH 2 EMPLOYEES OF THE REPAIR COMPANY, WAS STANDING IN FRONT OF BURNER UNIT. AT THE POINT WHEN THE PILOT IS IGNITED, THE UNIT BLEW UP. A COVER PLATE ON THE BURNER UNIT BLEW OFF AND STRUCK EMPLOYEE #1 IN THE CHEST, KILLING HIM. THE BOILER WAS MANUFACTURED BY THE H.B. SMITH COMPANY, OF THE 28 SERIES, MODEL C3-GO-25. THE BURNER UNIT WAS MADE BY POWER FLAME, INC. THE DAY AFTER ACCIDENT, A TEST OF THE UNIT'S OPERATION WAS CONDUCTED AT THE REQUEST OF THE MIDDLESEX COUNTY PROSECUTORS OFFICE. WITH THE MAIN GAS VALVE CLOSED, THE BURNER WAS STARTED. IT WAS FOUND THAT THE GAS FEED VALVE TO THE BURNER WAS OPENING CONCURRENTLY WITH THE PURGE. NORMALLY THE FEED VALVE OPENS AFTER A 90 SECOND PURGE AND DETECTION OF THE PILOT FLAME. AN EXAMINATION OF THE WIRING SHOWED THAT THERE WAS A MISTAKE MADE WHEN THE WIRING WAS RECONNECTED, SUCH THAT THE SAFETY MEASURE (PURGE-FLAME DETECTION) HAD BEEN BYPASSED. PROPER START-UP PROCEDURES WERE NOT FOLLOWED. THE REWIRING JOB SHOULD HAVE BEEN CHECKED AGAINST THE WIRING DIAGRAM. A START-UP CHECK TO CHECK THE SAFETY MEASURE SHOULD HAVE BEEN DONE WITH THE MAIN GAS VALVE CLOSED.