At least 49 people have been killed and hundreds injured in a fire that sparked a huge chemical explosion at a shipping container depot in Bangladesh. The death toll was expected to rise because some of the more than 300 people injured were in a serious condition. Volunteers, some with only flip-flops on their feet, recovered bodies from the smouldering, wreckage-strewn facility, saying there were more inside. The fire started late on Saturday at the huge depot in Sitakunda town, about 40 kilometres from the major south-eastern port of Chittagong. The site stored about 4,000 containers, many of them filled with garments destined for western retailers. Other containers that were storing chemicals exploded, engulfing firefighters, journalists and others in an inferno. People and debris were thrown through the air as the blaze turned the night sky orange and shook buildings kilometres away. Mujibur Rahman, director of BM Container Depot, the company operating the depot — which employs about 600 workers — said the cause of the fire was still unknown. Firefighters were still scrambling to put out the blaze on Sunday as more containers filled with chemicals exploded, a fire service official said. Newton Das said some of containers held hydrogen peroxide, while others were filled with sulphur. "It's really getting harder as toxic fumes engulfed the area," he told Reuters. Explosives experts from Bangladesh’s military have been called in to assist the firefighters. The initial explosion shattered the windows of nearby buildings and was felt as far as 4km away, officials and local media reports said. A surgeon in Chittagong said all doctors in the district had been called in to help. Social media has been flooded with appeals for emergency blood donations. The deaths of at least five firefighters was confirmed by Brig Gen Mainuddin, director general of the Bangladesh Fire Service. Another 15 firefighters were being treated for burns, he told AP. Hundreds of distraught relatives thronged the Chittagong Medical College and Hospital to find missing relatives, witnesses told Reuters. Bangladesh has a history of industrial disasters, including factories catching fire with workers trapped inside. Monitoring groups have blamed corruption and lax enforcement for these deadly incidents over the years. Global brands, which employ tens of thousands of low-paid workers in Bangladesh, have come under pressure to improve factory conditions in recent years. In the country’s large garment industry, which employs about four million people, safety conditions have improved significantly after reforms, but experts say accidents could still occur if other sectors do not make similar changes. In 2012, about 117 workers died when they were trapped behind locked exits at a garment factory in Dhaka. The country’s worst industrial disaster occurred the following year, when the Rana Plaza garment factory outside Dhaka collapsed, killing more than 1,100 people. In 2019, a blaze ripped through a 400-year-old area crammed with apartments, shops and warehouses in the oldest part of Dhaka, killing at least 67 people. Another fire in Dhaka, in a house illegally storing chemicals, killed at least 123 people in 2010. In 2021, a fire at a food and beverage factory outside the capital killed at least 52 people, many of whom were trapped inside by an illegally locked door.