Were South Korean workers forcibly injected with amphetamines?

Question

In a biographical article about the life of Jeon Tae-il, Wikipedia states that

As a tailor, Jeon witnessed the horrendous working conditions in the Seoul Peace Market... Such conditions included rampant tuberculosis... and the enforced injections of amphetamines to keep sleep-deprived workers awake and to work them overtime without proper compensation.

I can't easily find any other mentions of this, but I am skeptical for a few reasons:

• Amphetamine would be a extra cost for the employer, who could probably find cheaper ways of coercing employees to stay awake
• Amphetamine pills would probably be easier to administer compared to injections
• Although drug use to increase productivity is well established across many different countries throughout history, most of the other instances of it were voluntary

Note: For the purposes of my question, I'll interpret "enforced" as meaning that workers who refused the injections would lose their job. I don't think there's any implication of physical force being used against workers (although the article doesn't go into detail there).

Answer 1

According to a summary of the 1995 biographical film A Single Spark:

Tae-il is a tailor and starts working at the Seoul Peace Market, where he witnesses squalid working conditions, with cruel bosses demanding unthinkably long shifts.

The conditions mean that workers have tuberculosis due to poor ventilation in the packed working areas, with workers also having forced injections of amphetamines to keep them awake and ensuring overtime is completed.

In the book version A Single Spark: The Biography of Chun Tae-il, it doesn't say amphetamines specifically. Instead it says:

...the factory owners would buy anti-sleeping pills or administer injections to insure that workers stayed awake while working.

The 1979 Women's International Network News article "Korea: Women Workers" says (citing to Poverty & Power, vol. 1, No. 2, November 1978):

Owners provided them with pep pills or injections to keep them awake

Similarly, in a 1977 AMPO: The Japan Asia Quarterly Review it is stated in an article "Marginalization, Development and the Korean Workers Movement":

...to work for two or three days without sleep , shop owners providing pep pills or injections to keep them awake.

See also the 1984 The Working and Living Conditions in South Korea in the stage of the export-oriented Industrialization (1965-1980) for more information.