No.1 kiln was sht down @ 20:00 hrs on 3/31/04 for maint. repairs. Scope of work incl: replacement of thrust roller, chg F.D. fan bearing & balance, modification of burner to manufacturer spec. Work was completed 4/2/04. Maint returned kiln to operations & operations then put kiln in service. @ 20:00 a blast was heard on south end of unit.