A government investigation found poor quality construction materials and building code violations were among the "series of irregularities" that caused the collapse of a building housing clothing factories last month in Bangladesh, the committee head said.
The disaster killed more than 1,000 workers and highlighted the hazardous working conditions in Bangladesh's 20 billion dollar clothing industry and the lack of safety for millions of workers who are paid as low as 38 dollars a month.
"The owner used extremely poor quality of iron rods and cement," committee head Khandker Mainuddin Ahmed said a day after submitting its report to the government. "There were a series of irregularities."
The report also found that building owner Sohel Rana had permission to build a six-story structure and added two floors illegally so he could rent them out to clothing factories. Past statements from authorities said the owner had permission for a five-story structure and added three floors illegally.
The report also said the building was not built for industrial use and the weight of the heavy garment factory machinery and their vibrations contributed to the building collapse. Those factors had previously been cited.
The committee recommended that Rana and the owners of the garment factories be sentenced to life in jail if they are found guilty of violating building codes.
Rana, three engineers and four factory owners have been arrested.
The building was shut down briefly after workers spotted cracks in its walls and pillars a day before the April 24 collapse. But the garment factory workers were called back to work, many of them forcefully.