In April 1995, cracks began to appear in the ceiling of the south wing's fifth floor, but the only response by Lee and his management staff involved moving merchandise and stores from the top floor to the basement.
On the morning of June 29, the number of cracks in the area increased dramatically, prompting managers to close parts of the top floor.
The store management failed to shut the building down or issue formal evacuation orders, as the number of customers in the building was unusually high, and it did not want to lose the day's revenue.
However, the executives themselves left the premises as a precaution.

When civil engineering experts were invited to inspect the structure, a cursory check revealed that the building was at risk of collapse; the National Geographic documentary programme Seconds From Disaster indicates that the facility's manager was examining the slab in one of the restaurants on the fifth floor only hours before the collapse, when, unknown to him, vibration from air conditioning was radiating through the cracks in the concrete columns, and the floor opened up.

Five hours before the collapse, the first of several loud bangs was heard emanating from the top floors, as the vibration of the air conditioning caused the cracks in the slabs to widen further.
Amid customer complaints of vibration, the air conditioning was turned off, but the cracks in the floors had already grown to 10 cm wide.
Around then, it was realized that collapse of the building was inevitable, and an emergency board meeting was held.
The directors suggested to Lee that all customers should be evacuated, but Lee angrily refused to do so for fear of revenue losses.
However, Lee himself left the building safely before the collapse occurred.
He did not even inform his own daughter-in-law, Chu Kyung Young, who was one of the employees in the building, of the imminent danger.
She became trapped in the rubble and was rescued only days later.

At about 5:00 p.m., Korea Standard Time (UTC+9:00), as the fifth floor ceiling began to sink, store workers closed off all customer access to the fifth floor.
According to Seconds From Disaster, the store was packed with hundreds of shoppers 57 minutes before the collapse, but Lee did not close the store or carry out repairs during that time.
When the store started to produce cracking sounds at about 5:52 p.m., workers began to sound alarms and evacuate the building, but it was too late: the roof gave way, and the air conditioning units crashed through into the already-overloaded fifth floor.
The main columns, weakened to allow the insertion of the escalators, collapsed in turn, and the building's south wing began pancaking into the basement.
In less than twenty seconds, all the columns in the store's south wing had given way, killing 502 people and trapping more than 1,500 inside.
The disaster resulted in about ₩270 billion (approximately US$216 million at the time and approximately US$364 million in 2020) worth of property damage.
In April 1995, cracks began to appear in the ceiling of the south wing's fifth floor, but the only response by Lee and his management staff involved moving merchandise and stores from the top floor to the basement. On the morning of June 29, the number of cracks in the area increased dramatically, prompting managers to close parts of the top floor. The store management failed to shut the building down or issue formal evacuation orders, as the number of customers in the building was unusually high, and it did not want to lose the day's revenue. However, the executives themselves left the premises as a precaution.
When civil engineering experts were invited to inspect the structure, a cursory check revealed that the building was at risk of collapse; the National Geographic documentary programme Seconds From Disaster indicates that the facility's manager was examining the slab in one of the restaurants on the fifth floor only hours before the collapse, when, unknown to him, vibration from air conditioning was radiating through the cracks in the concrete columns, and the floor opened up.
Five hours before the collapse, the first of several loud bangs was heard emanating from the top floors, as the vibration of the air conditioning caused the cracks in the slabs to widen further. Amid customer complaints of vibration, the air conditioning was turned off, but the cracks in the floors had already grown to 10 cm wide. Around then, it was realized that collapse of the building was inevitable, and an emergency board meeting was held. The directors suggested to Lee that all customers should be evacuated, but Lee angrily refused to do so for fear of revenue losses. However, Lee himself left the building safely before the collapse occurred. He did not even inform his own daughter-in-law, Chu Kyung Young, who was one of the employees in the building, of the imminent danger. She became trapped in the rubble and was rescued only days later.
At about 5:00 p.m., Korea Standard Time (UTC+9:00), as the fifth floor ceiling began to sink, store workers closed off all customer access to the fifth floor. According to Seconds From Disaster, the store was packed with hundreds of shoppers 57 minutes before the collapse, but Lee did not close the store or carry out repairs during that time. When the store started to produce cracking sounds at about 5:52 p.m., workers began to sound alarms and evacuate the building, but it was too late: the roof gave way, and the air conditioning units crashed through into the already-overloaded fifth floor. The main columns, weakened to allow the insertion of the escalators, collapsed in turn, and the building's south wing began pancaking into the basement. In less than twenty seconds, all the columns in the store's south wing had given way, killing 502 people and trapping more than 1,500 inside. The disaster resulted in about ₩270 billion (approximately US$216 million at the time and approximately US$364 million in 2020) worth of property damage.
Sampoong Department Store collapse