In pics: Bangladesh authorities accused of blast that nearly killed at least 49 and injured hundreds

Some containers were still smouldering on Monday, more than 36 hours after the explosion, preventing rescuers from checking the area around them for victims.

Around a dozen of the 300 injured were in critical condition. 

The nine dead firefighters are the worst toll ever for the fire department in the industrial-accident-prone country, where safety standards are lax and corruption often enables them to be ignored.

"The depot authority did not inform us that there were deadly chemicals there. Nine of our officers were killed. Two fighters are still missing. Several people are also missing," fire department official Mohammad Kamruzzaman told AFP.

Purnachandra Mutsuddi, who led the fire-fighting effort at the 26-acre facility on Saturday night, said it “didn't have any fire safety plan" and lacked firefighting equipment to douse the blaze before it turned into an inferno. 

"The safety plan lays out how the depot will fight and control a fire. But there was nothing," Mutsuddi, an assistant director of the Chittagong fire station, told AFP.

"They also did not inform us about the chemicals. If they did, the casualties would have been much less," he said.

The B.M Container Depot in Sitakunda, an industrial town 40 kilometres (25 miles) from Chittagong Port, is a joint venture between Bangladeshi and Dutch businessmen with around 600 employees, and began operations in 2012.

Police have yet to lay charges over the fire. "Our investigation is going on. We will look into everything," said local police chief Abul Kalam Azad.

Wisps of smoke rose into the bright morning sky from dozens of twenty-foot containers at the depot on Monday.

"Some 30-40 containers are still smouldering," said fire department inspector Harunur Rashid.

"Fire is under control. But chemicals are main problems."

Once the flames are entirely out rescuers will search the area for more victims, he said.

Mujibur Rahman, a director of B.M. Container Depot, said the cause of the initial fire remained unknown.

The container depot held hydrogen peroxide, according to fire service chief Brigadier General Main Uddin, and witnesses said the entire town shook when the chemicals exploded.

"The explosion sent fireballs into the sky," said Mohammad Ali, 60, who runs a nearby grocery store. "Fireballs were falling like rain. 

"We were so afraid we immediately left our home to find refuge," he added. "We thought the fire would spread to our locality as it is very densely populated."

Rakibul Alam Chowdhury from the Bangladesh Garment Manufacturers and Exporters Association (BGMEA) said that about 110 million dollars worth of garments were destroyed in the fire. 

"It is a huge loss for the industry," he said.

Elias Chowdhury, the chief doctor in Chittagong, said doctors at multiple hospitals had been called back from holidays to help treat the hundreds of injured.