Emission of toxic ammonia at a Chittagong fertiliser factory was brought under control yesterday, around 11 hours after a gas tank exploded there, leaving nearly 250 people sick.
Sixteen fire-fighting units managed to stop the emission at the factory of DAP Fertiliser Company Ltd in Anwara upazila around 9:00am by dissolving the toxic gas in water, said fire service officials.
“We are still applying water to dissolve the gas completely,” Md Jashim Uddin, deputy additional director of fire service and civil defence in Chittagong, told this correspondent around 4:00pm.
The authorities were yet to ascertain the reason behind the explosion.
Visiting the plant yesterday morning, Bangladesh Chemical Industries Corporation (BCIC) Chairman Mohammad Iqbal said, “It is just an accident.”
An air quality test found the presence of ammonia in the air at 600ppm (parts per million) in a radius of 140 metres from the source of emission at 3:00am. However, it was 20ppm beyond a radius of 200 metres, he said.
According to Jashim, they found the level of ammonia below 25ppm in air quality check at 9:00am.
If the level of ammonia is five ppm in the air, people could bear it. “But when we arrived here at night, we found it at 600 ppm,” he added.
This correspondent yesterday found that leaves of many trees were burned in vast areas to the north and north-west of the factory.
A similar picture was seen in the airport area, around three kilometres from the factory.
There was still an acrid smell in the factory area around 3:00pm.
Simul Sen, a partner of AH Enterprise that cultivates fish in a nearby 300-acre pond, claimed that following the explosion, 10 tonnes of fish in the pond died till afternoon.
“When we came here this morning, we saw hundreds of dead fish floating all over the pond,” added Simul.
Talking to this correspondent, Edris Ali, associate professor of Chemistry at Chittagong Mohsin College, said ammonia is a very corrosive gas and it slowly diffuses into the air.
It increases the pH level in water which impacts the aquatic ecosystem. Fish in ponds adjacent to the affected area is dying because of the high pH level in water, said Edris, who worked on several environmental projects.
Though ammonia in the affected area was dissolved in water, the toxic gas-mixed water would end up in water bodies, canals and river and eventually impact the aquatic ecosystem.
But in course of time, the high concentration of ammonia would diffuse into air and water, and its adverse impact would go away, he added.
Meanwhile, nine of the 52 people, admitted to Chittagong Medical College Hospital after falling sick from inhaling toxic gas, were released yesterday.
The condition of most of the other patients improved, said hospital sources.
DAP officials said the two-unit factory started production in 2006 with a production capacity of 1,600 tonnes of diammonium phosphate fertiliser a day.
There is a 5000-tonne mother storage tank from which ammonia is carried to two 500-tonne tanks through pipelines. And the raw material is supplied from the two tanks to the plant during production, they said.
Amal Barua, managing director of DAP, said one of the two 500-tonne tanks exploded on Monday night with around 250 tonnes of ammonia in it.
He said the lifespan of the container was 25 years and it was regularly monitored.
Asked about the reason behind the explosion, he said it was hard to say at this point why it happened.
The BCIC formed a 10-member technical committee, headed by BCIC Director (technical and engineering) Ali Akkas, to probe the incident.
The reason behind the gas tank explosion would be known after completion of investigation, BCIC Chairman Iqbal told reporters.
If it is found that the gas explosion occurred due to negligence of the officials concerned, the BCIC would take stern action against those responsible.
“We have communicated with the company that built the container. They wanted some information from us. We will send all information as early as possible,” he said.
A BCIC source said a representative of the Chinese construction company that built one of the two units of the plant would arrive in the port city in a day or two.
Department of Environment officials said the DoE formed a 10-member committee to investigate the incident.
Besides, Chittagong district administration formed a three-member probe committee headed by Additional District Magistrate Mominur Rashid.
It would submit a report in seven working days, said Chittagong Deputy Commissioner Mesbah Uddin.
ACCOUNTS OF WITNESSES
One of the two 500-tonne tanks exploded at 9:50pm on Monday when workers at the factory were changing shift.
Around 30 workers were inside the factory during the blast, said a number of factory workers.
Wind carried the toxic gas emitted from the exploded container towards the Karnaphuli river and Patenga area in the port city.
The residents in Naval Academy, Chittagong airport, Chittagong port, Halishahar and Agrabad areas got an acrid smell and many of them fell sick.
Atiqur Rahman, an operator at the DAP factory, said he heard a loud bang immediately after crossing the main entrance to the factory.
He then saw black smoke billowing out of the factory.
Many of the staffs were hurrying to get out of the place, said Atiqur, who works in night shift.
Ahsan Ullah, an Ansar member at the DAP factory, said, “I thought it was a fire when I saw a cloud of smoke rising from the exploded tank. It went several hundred feet upward.
“After a while, I found it hard to breathe. At one point, I had almost fainted but I somehow made my way to the gate,” he added.