Titas Managing Director Mir Moshiur Rahman said a three-member investigation committee was formed on Thursday.
He visited the spot on Thursday and said the committee had been ordered to submit its findings within seven business days.
A fire swept through the food and cigarette packaging factory of Tampaco Foils Limited on Saturday following a huge explosion. The disaster, Bangladesh's worst since the Rana Plaza collapse, left 34 people dead and more than 40 people injured.
Ten others still missing, the district administration said on Thursday.
The district administration, the fire service and the labour ministry have formed separate committees to look into the incident.