The 430 employees at the Dasan 120 Call Center are "emotional laborers."

Many of the callers they respond to are abusive and often use sexually explicit and violent language, which causes the employees, who are mostly female, to suffer from emotional insensitivity, loss of self-esteem, insomnia, depression and high blood pressure.

Almost 400,000 people across the country work in call centers.

Emotional workers are people asked to show a required emotion toward customers or clients. They include flight attendants, sales clerks, restaurant waiting staff, doctors and nurses. The number of such workers is increasing as more jobs become services-based.

Jeon Eui-sil, a manager at the Dasan Call Center, said the number of employees who are verbally harassed by callers has increased so much that the company decided to address the issue.

Starting in the summer of 2012, the center began to take steps against abusive callers. The manual it developed instructs employees to first warn such callers about the possible consequences of their actions. If the callers do not stop, the employees can hang up. In a worst-case scenario, the company can file a complaint against the abusers with the prosecution. In April, the center filed 10 such complaints. That is an increase over the seven complaints it filed last year.

"These steps are helping us significantly," said Jeon.

Between spring 2012 and early this year, the number of abusive calls has dropped from an average of 76 to 13 per day.

Not all workplaces, however, can afford to take such protective measures for their employees, which has prompted a call for assistance from nongovernmental organizations (NGOs).

In April, local NGOs that advocate workers' rights rallied in downtown Seoul, calling for awareness and action. Among the participants was Philip J. Jennings, secretary-general of the UNI Global Union, a global federation for skilled and service workers.

Some lawmakers are also starting to lay the groundwork for the legal protection of emotional laborers. Rep. Han Myeong-sook, a proportional representative, has proposed such bills, which are waiting to be reviewed by the National Assembly's labor's committee.

Likewise, the Emotional Labor Solution Institute, a private initiative, is working to help emotional laborers. Since the institute opened in March, director Yun Seo-young and her team have been counseling such workers on how to deal with abusive callers and training emotional labor therapists.

Once a telephone operator herself, Yun said her experience compelled her to do something to ease the pain.

"Through training, emotional workers can understand themselves and others better. Eventually, they learn to grow resilient to malicious language by callers and to not take abusive words personally."

Her organization is one of several that have recently sprung up. The number of organizations like hers is likely to grow.