Bangladeshi police have arrested the owner of a factory where at least 52 people died in an inferno, as it emerged that children as young as 11 had been working there. Police said the owner of the food factory and four of his sons were among eight people detained over the fire that broke out on Thursday and raged for more than a day. The blaze began in the evening at the five-storey Hashem Foods factory in Rupganj, just outside Dhaka. A separate inquiry has been launched into the use of child labour at the facility. Jayedul Alam, police chief for Narayanganj district where the factory is located, said the entrance had been padlocked at the time of the blaze and the factory breached multiple fire and safety regulations. Many of those who died were trapped and several workers jumped from upper floors, with dozens suffering injuries. Emergency services found 48 of the bodies on the third floor of the factory. A fire services spokesperson said the exit door to the main staircase had been padlocked. Highly flammable chemicals and plastics had been stored in the building. Monnujan Sufian, state minister for labour, said inquiries had begun into the use of child workers at the factory. Sufian said she had spoken at a hospital to two survivors aged 14. One woman said her 11-year-old nephew had been working at the factory and was missing, feared dead. Bangladesh pledged reforms after the Rana Plaza disaster in 2013 when a nine-storey complex collapsed, killing more than 1,100 people. But there have been a series of fires and other disasters since then. In February 2019 at least 70 people died when a fire ripped through Dhaka apartments where chemicals were illegally stored. The country has a history of industrial disasters, including factories catching fire with workers locked inside. Continuing corruption and lax enforcement have resulted in many deaths over the years, and big international brands, which employ tens of thousands of low-paid workers in Bangladesh, have come under pressure to improve factory conditions after fires and other disasters killed thousands of people. The factory that caught fire on Thursday was a subsidiary of Sajeeb Group, a Bangladeshi company that produces juice under Pakistan-based Shezan International, said Kazi Abdur Rahman, the group’s senior general manager for export. According to the group’s website, the company exports its products to countries including Australia, the US, Malaysia, Singapore, India, Bhutan, Nepal and to the Middle East and Africa.