Seoul Metro, which operates eight subway lines in the capital, turned 1,285 indefinite-term contract workers into regular employees in March.

In terms of working hours, there is little difference between the two categories of workers, but indefinite-term contract workers are usually paid about 50 to 60 percent of what regular employees receive.

According to parliamentary inspection data provided by Seoul Metro to Rep. Yoo Min-bong of the opposition Liberty Korea Party, 108 of the contract-turned-regular workers are relatives of regular employees who had joined the company earlier. Thirty-one are children of existing regular workers, 22 brothers and sisters, 15 uncles, 12 spouses, 12 cousins and six parents. The other 10 are other relatives.

One reportedly must pass three relatively easy stages -- resume screening, an interview and physical examination -- to be employed as an indefinite-term contract worker, while passing five stages is required to be hired as a regular employee. The two difficult stages skipped for recruiting indefinite-term contract workers are written and personality tests.

Allowing this as a way to become regular staff amounts to a special favor for relatives of existing employees and effectively robs those who apply through the normal procedure of regular employment. The average annual pay of Seoul Metro employees exceeds 67 million won ($59,000). The acceptance rate in the open competitive test for jobs in the company is about 1.8 percent.

As many as 65 of the 108 regulars joined Seoul Metro as indefinite-term contract workers after the death of an outsourced maintenance worker, who died when he was hit by a train while repairing a platform door in May 2016. The accident, which made a nationwide stir, led to the company’s decision to suspend outsourcing platform maintenance jobs and hire related personnel directly as indefinite-term contract workers.

They may have applied to enter Seoul Metro with the expectation that they would eventually become regular staff.

Rumors of such a looming conversion were said to have circulated among existing employees at the time. They are suspected of having encouraged their relatives to apply for indefinite-term contract jobs. Even the wife of a senior personnel manager was turned to regular staff. This was discovered some time after the list of 108 employees’ relatives had been disclosed.

In July 2017, Seoul Metropolitan Government announced it would convert indefinite-term contract workers of all its affiliated institutions, including Seoul Metro, into regular employees.

Rep. Kim Yong-tae of the party said, “The data came from a survey of just 11.2 percent of about 17,000 Seoul Metro employees, so if all of them responded, the number of regular employees’ relatives who turned from contract workers to regular staff may exceed 1,000.” He also said the Korean Confederation of Trade Unions had asked the Seoul Metro union to tell its members not to respond to a survey the Seoul city government is reportedly considering amid rising criticism over the conversion of contract workers into regulars.”

A video clip, disclosed by news media Monday, showing violence by the Seoul Metro union upon the company management is astounding.

During labor-management negotiations on Dec. 31, a union leader is seen swooping upon a company-side negotiator from behind and trying to strangle him.

Afterward, eventually, both sides agreed to turn indefinite-term contract workers into regular employees. By the way, Seoul Metro reportedly changed not only maintenance contract workers but also contract workers in non-maintenance jobs such as company cafeteria and barbershop workers into regular employees. The union’s strong influence cannot be suspected.

There is even suspicion that some of the 108 workers in question joined Seoul Metro under instructions by the umbrella union organization apparently to tighten control over the Seoul Metro union. They may have played a leading role in pushing for the conversion of contract workers into regulars. Seoul Metro did not raise issue over the violence during collective bargaining.

The Board of Audit and Inspection must thoroughly examine suspicions about Seoul Metro’s employment practices.

Hiring irregularities are a crime which infuriates and frustrates young job seekers and others. Those suspected of committing serious wrongdoings must face a judicial investigation.

Given other employment abnormalities at state-owned enterprises and financial institutions, the board needs consider expanding inspection to all other public entities.

As Seoul Metro said it had followed the instructions from the Seoul government, the capital municipality will not be free from responsibility.