Have you ever woken up after a night out with hangover-induced anxiety? Well, a contractor in Japan recently had good reason to after passing out drunk on the street and losing a USB stick containing sensitive information of 460,517 people – the entire population of the city of Amagasaki.

The employee – reportedly a man in his 40s – worked for a company subcontracted by technology company Biprogy Inc, which itself was commissioned by the Amagasaki city government to handle COVID-19 relief subsidies.

The device contained information such as zip code, date of birth, and date of becoming a resident for all 460,517 citizens, Biprogy revealed in a statement. It also included 360,573 cases of tax information; data on 74,767 households “subject to temporary special benefits such as tax-exempt households”; banking information of 69,261 households receiving child allowances; and banking information of 16,765 households receiving livelihood protection benefits.

According to a detailed timeline of events provided by Biprogy, on June 21, the employee stored the data on the USB stick to transfer it to another information center. Importantly, the drive was supposed to be wiped afterward, then stored in a designated location – but the employee was not instructed to do this, and instead put the USB drive in his bag. 

After this, at 7:30 pm, four employees of the company went out to eat and drink. At 10:30 pm, the group parted ways, and the man was confirmed to have the bag containing the USB stick in his possession. 

However, things apparently went south from that point. At 3 am on June 22, the man was seen sleeping on the street, and his bag was nowhere to be seen. The man, very understandably, called his employer to take a sick day at 9 am. He reported the bag missing to his employer at 2 pm.

On June 22, the location information of a mobile phone also in the bag was confirmed. The employee retraced his hazily-remembered steps accompanied by 30 police officers on June 24, according to The Asahi Shimbun, with the bag eventually being found in an apartment in Suita, Osaka Prefecture.

Luckily, the data was reportedly encrypted and locked with a password, and no data breaches have so far been reported. However, Biprogy stated that they will be monitoring the dark web in case the data pops up there, and a hotline has been set up by the city for those concerned about their data.

“We will work to regain our residents’ trust by heightening awareness of the importance of protecting personal information,” the city said in a statement reported by the Guardian.