HWASEONG/SEOUL -- The deadly fire that killed at least 23 people at a lithium battery factory in Hwaseong, Gyeonggi Province, may have been worsened by deficiencies in prevention measures and unsafe working environments, with a report that a fire had broke out two days before the Monday outbreak.

While the exact cause of the fire will be determined through further forensics, experts believe that the lack of a proper evacuation route may have worsened the fire's effects. The proximity of the entrance and exit to the battery storage area may have increased the loss of life, they added.

"There must have been a huge 'thermal runaway' phenomenon that caused the fire, given that more than 34,000 lithium batteries were stored there," said Dr. Kim Soo-young, a researcher at the National Fire Research Institute who participated in a joint investigation to determine the cause of the fire at primary battery maker Aricell factory.

The place of ignition is where finished primary batteries for the military are inspected and packaged. As military batteries are made to last for more than a year, they are more dangerous in a fire because they have a larger capacity than regular batteries.

"The batteries weren't clustered in one place, but rather were scattered all over the place," she said, speculating that the first battery to ignite may have ricocheted several meters, impacting other batteries and setting off a chain reaction of flames.

As lithium batteries are known to be explosive and the manufacturing potentially dangerous, the probe into the Hwaseong fire focused on why the damage could not be prevented and whether there was any negligence on the part of factory officials that allowed the fire to start.

Police have filed criminal charges against five people responsible for the fire, reportedly including Aricell CEO Park Soon-kwan, on charges of professional negligence resulting in deaths. Police have also banned all five from leaving the country. Park was also charged with violating the Serious Accident Punishment Act.

Critics also point to a previous fire that broke out Saturday and the company reportedly had not taken any safety measures later other than self-extinguishing, which could have led to the disaster.

The company acknowledged that a fire broke out on the first floor of the building on Saturday afternoon. The fire was caused by a worker injecting electrolytes into the battery, which caused the temperature of the battery to rise rapidly. "The fire was extinguished by the workers themselves with a fire extinguisher, and the size and type of fire is different from the cause of this fire," the company said. "We did not call 911 because we thought there was no more problem," the company said.

Tuesday's investigation lasted about four hours and 10 minutes from noon to 4:10 p.m., which was delayed due to the recovery of an additional unidentified body Tuesday morning.

The joint identification operation conducted Tuesday included 40 officials from nine organizations including the police, the National Forensic Service and the Ministry of Employment and Labor.

The police will also look into whether proper equipment prevention measures were in place to extinguish the fire early on and if the evacuation was done properly. The authorities will investigate whether lithium, a spontaneously combustible material that can catch fire when exposed to high temperatures, was properly stored in a designated area.

With one more body being recovered from the scene Tuesday at 11:30 a.m., the number of deaths increased to 23.

The body found Tuesday is believed to be the remaining missing person the fire authorities have been searching for. The recovered body, reportedly a foreign laborer, was found near the ignition point on the second floor of the factory. However, due to the severe damage to the body, the identification of the body is likely to take time, authorities added.

Fire authorities initially said that 20 of the victims were foreign workers, but later revised the number down to 18, including 17 Chinese nationals and one Laotian. Fire authorities confirmed two bodies, a Korean man in his 50s and a man in his 40s, a Chinese who naturalized to South Korea. The foreign victims, mostly Chinese women in their 30s and 40s, were hired for temporary positions at the factory that was under pressure to meet the delivery time of the batteries, according to local reports, quoting insiders.

Meanwhile, the mayor of Hwaseong city requested the government declare the area a special disaster area at a Tuesday briefing at the fire site.

Mentioning that the local government-level response to a large-scale human disaster is limited, much of the government's support is needed to help transport the bereaved families abroad for quick identification, said Mayor Jeong Myeong-geun.

Hwaseong City also believes that a national response should be made to support the overall disaster recovery, including funeral support, disaster relief and compensation.

If the area is declared a special disaster area, a portion of the costs associated with damage restoration may be funded by the government.

Before declaring Hwaseong City a special disaster area, the government will first provide 1 billion won ($720,990) of emergency support to Hwaseong City to be used for early damage restoration, including the disposal of debris around the disaster site and the promotion of safety measures to prevent further damage, according to the Central Disaster Safety and Countermeasures Headquarters at the Tuesday briefing.

The DNA identifications of the deceased are expected to take several days, as most of the bodies were severely damaged and require DNA comparison with the family members based overseas.

If the deceased foreigners have family members in South Korea, DNA can be collected and matched quickly, but if not, DNA will be collected locally through consulates in their home countries and sent for matching.

Prime Minister Han Duck-soo called for providing special care to the families of 18 foreign workers who were killed in a battery plant fire and instructed the interior ministry and other relevant ministries to thoroughly determine the cause of the fire and provide immediate assistance to the victims and their families.

"In particular, given the large number of foreign workers who lost their lives, I ask the Foreign Ministry and other agencies to swiftly identify them, establish a cooperation mechanism with the relevant diplomatic missions and provide close care throughout the entire process of giving updates to treating the injured, arranging funerals and offering compensation for damage," he said.

He urged ministries to combine their capabilities to overcome the crisis and called on the National Assembly to show bipartisanship in passing a bill for the establishment of a new Ministry of Population Strategy Planning.