SQ1 and E1 were responding to a systems alarm and found heavy smoke coming from a large industrial building. BAT 1 made a quick 2nd alarm then went to a 3rd about 30 minutes later. 181 Safety, AP1, AP2 Aerial Attack, E1 Fire Attack, E25 Pumped, BAT 1 Command, BAT2 South Division, HR4 Ventilation, Q4 water supply for AP1, SQ1Fire Attack, E11 Water Supply for AP2, E5 Fire Attack, SQ5, SQ2 E10,SQ12,E328, E7, 191, 192, E2 MA1, all investigators also responded to the alarm.