The source of a toxic gas leak in Karachi's Keamari area remained unclear on Tuesday as officials from the Sindh health department confirmed the death toll had risen to at least 14, two days after residents from adjoining areas rushed to hospitals complaining of breathing difficulties.

Meanwhile, dozens of protesters, belonging to residential areas close to the affected area, gathered in Keamari's Jackson Market, demanding answers from authorities on the deaths that have been caused from the mysterious gas.

Addressing a press conference along with Sindh Minister for Local Government Syed Nasir Hussain Shah on Tuesday afternoon, Karachi Commissioner Iftikhar Shallwani said multiple theories were being considered but thus far the source of the gas and its nature was still unknown. He added that an investigation was still ongoing.

Dr Ziauddin Hospital spokesperson Amir Shehzad told Dawn.com that nine deaths took place at the hospital's Keamari Campus over the course of the past two days. According to the police, two other deaths were reported at Kutiyana Hospital.

Meanwhile, officials from the Sindh health department added that two more deaths were reported at Civil Hospital Karachi while one more was reported at Burhani Hospital.

Dozens of others have been hospitalised in various medical facilities across the city with officials confirming that over 250 individuals were discharged after treatment.

Shehzad said approximately 250 patients had been brought to Dr Ziauddin Hospital with 100 brought in on Monday alone.

He said most patients were released after being treated, adding that five patients had been admitted to the intensive-care unit (ICU) whose conditions were also improving.

According to the hospital spokesperson, the patients, who were from various areas of the city, had shown symptoms including difficulty breathing, dizziness while some were also throwing up.

Jinnah Postgraduate Medical Centre Executive Director Dr Seemin Jamali told Dawn.com that the hospital had received 27 patients on Monday night, all from the Keamari area.

Jamali said that one of the patients had acute exasperation asthmatic attacks and was in critical condition in the intensive care unit (ICU).

She added that the remaining 26 patients had been discharged after three to four hours.

According to Jamali, the patients all came from a specific area in Jackson Bazaar near a mosque and behind the railways line.

She said that during the day things had been stable but patients started to come in on Monday night.

"Some gas had been emitted from there," she said, adding: "We express solidarity with the people living in that area."

Police surgeon Dr Qarar Ahmed Abbasi had said two female patients were brought to the Dr Ruth Pfau Civil Hospital Karachi and they were discharged after first medical aid.

Speaking to Dawn.com, Sindh Env­ironmental Protection Agency (Sepa) spokesperson Mujtaba Baig said the organisation had conducted an initial survey yesterday and talked to people in the area.

He said they were unable to determine the exact source or cause of the toxic gas, adding that there was "some sort of activity" but they couldn't yet be certain what it was.

Last night, Sindh Chief Minister Murad Ali Shah had ordered the evacuation of residents from the affected areas, regretting that the "bad smell" was not receding and people were still being affected.

Possible cause

In his pressser on Tuesday, Karachi Commissioner Shallwani said the incident was a "localised event".

He said it had been two days since the toxic gas leak started but added that it was restricted to just one locality of Karachi.

Shallwani urged the media not to cover the event in a way that created a panic in the metropolis.

The commissioner said an investigation into the gas leak is ongoing and added that samples from those admitted in hospitals had also been collected. Additionally, he said post-mortem examination reports of those who died will take at least 72 hours to be issued.

Shallwani said once reports are published, they can determine the reason for the gas leak and its nature.

Authorities were alerted to the incident when people in the Keamari area began rushing to nearby hospitals with severe breathing problems on Sunday night. The concerned authorities were not sure about the exact cause of the incident.

"We are still clueless to find out the possible cause of the incident," Karachi police chief Ghulam Nabi Memon had told Dawn on Monday.

He added, however, that senior police officers were working in coordination with doctors to determine the exact nature of the incident.

Earlier on Monday, Shallwani had informed a Sindh cabinet meeting that a ship that was offloading soybean or a similar substance could be the probable cause of the toxic gas.

"When offloading from this ship is halted, the smell too diminishes," he reasoned.

At this, CM Shah directed to check the particular container on the ship. The commissioner responded that offloading from the ship had already been stopped.

However, when contacted, Federal Minister for Maritime Affairs Ali Zaidi told Dawn.com on Tuesday that reports of the gas emanating from a soybean ship were "absolute rubbish" as the crew and the vessel were fine.

He said he had personally visited the port and the hospital yesterday.

Zaidi said it was interesting that the gas could only be smelt at night. He reiterated that nothing was happening at the port.

An initial investigation into the incident by Sindh Environmental Protection Agency (Sepa) on Monday showed that toxic gas had leaked from the terminal/s storing crude oil and petroleum products located within the residential areas.

"Today, our team has carried out a detailed inspection of the affected residential areas in Keamari and found that they all are surrounded by several storage units meant to keep imported crude oil and petroleum products," said Sepa director general Naeem Mughal.

He added that companies periodically carried out repair and maintenance of their units and it was likely that a toxic gas leaked during such a process.

The team, he said, also interviewed the families whose loved ones either died in the incident or received medical treatment.

"The families which suffered immediate casualties had their houses located just adjacent to a storage unit in Railway Colony. The department, however, would be able to share conclusive findings in a day or two after examining the samples it has collected from various affected places and hearing out representatives of the Karachi Port Trust (KPT) and companies maintaining their units in residential areas," Mughal said, adding that these samples included air quality samples.

Other areas which the team visited were Jackson and Shireen Jinnah Colony.

KPT denies gas leakage

Karachi Port Trust (KPT) chairman Jamil Akhter on Monday said the port was functioning normally.

"All terminals have been checked and from nowhere, gas leakage has taken place," he claimed.

He had said that news being spread on social media about the gas leakage from the port was wrong and untrue.

"I assure you that gas leakage has not taken place from the port," he said.

Akhter said that all berths at the KPT were being examined.

The port chairman said that the Pakistan Navy had taken some samples and hoped that the report would be received soon.

While the police, SEPA, Pakistan Navy and KPT were all in the dark about the nature of the toxic gas or even the source of its leakage, residents of the densely-populated Railway Colony along the main Keamari Road cast doubts over a huge crude oil storage facility near their area.

"We have serious suspicions about these tanks and the authorities must pay a detailed visit here," said Muhammad Hamid, a resident of Railway Colony which was one of the affected areas.