Incheon International Airport subjected nearly 40,000 passengers to full-body scans without warning for the last three years, according to Democratic Party lawmaker Park Ki-choon.
In a parliamentary audit of the country's main airport Thursday, Park pointed out that the airport administered scans which make the passenger appear naked of some 40,000 people who were randomly and unknowingly assigned code "SSSS" on their boarding passes from 2010 until May this year.
The airport claimed the passengers were subjected to the scans for "good reason," but most were given no explanation what that good reason might have been.
The SSSS code is issued by the airlines solely based on the data provided by the U.S. Transportation Security Administration.
In most cases, the code was assigned to people who booked one-way tickets, paid cash or bought on the day of travel were subject to the code.
Incheon airport said full-body scans are administered to people who are deemed to pose threat to the safe operation of the aircraft and the safety of the passengers.
However, they included a three-year-old child and a 70-year-old.