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Slate, which was used a lot as roofing material in the past, contains asbestos, a Group 1 carcinogen that is banned from use. There were concerns that asbestos could disperse into the air as it corrodes over time, but when the icicles hanging from the ends of the slate roofs were analyzed, asbestos was indeed detected.

Jang Se-man, an environmental reporter, covered the story exclusively.

<Reporter>

Lee Seong-jin, who had one lung removed due to malignant mesothelioma before he turned 20.

The only known cause of this cancer is exposure to asbestos, and the government’s investigation found that it was likely due to exposure to slate in the neighborhood where he lived as a child.

[Lee Seong-jin/Asbestos victim: My house also had an entire slate roof, and I would pick up (the slate) with my hands and play with it like I was fighting with a sword… .]

An environmental group analyzed icicles hanging from slate roofs in a residential area in Sanggye-dong, Seoul, which is scheduled for redevelopment, and found that they contained chrysotile, a group 1 carcinogen.

Four out of six samples contained 0.5 to 1.75% of chrysotile fibers.

Slate is made by mixing cement and asbestos, and there was a high risk that it would disperse into the air after weathering for decades after construction, but analysis of the icicles confirmed that it actually came out of the roof.

This means that when it rains, it can flow out into the surrounding area with rainwater.

[Choi Ye-yong/Director of the Environmental Health Citizens’ Center: When snow falls on an asbestos slate roof, it affects not only the people living in that house, but also the people living in the neighborhood.]

Over the past 10 years, we have been working on removing slate roofs containing asbestos from 300,000 buildings, but there are still over 900,000 slate buildings left.

The problem is that most of the houses are old houses where the elderly live, so even if they receive millions of won in government subsidies for demolition, they are reluctant to pay the cost of replacing them with new roofing materials.

[Slate house resident: We all know that there are carcinogens. We know that, but we are barely able to live here, so it is difficult to replace them.]

Workers spraying paint on slate roofs in the UK. If slate demolition is difficult, a special coating containing a fixative is sprayed instead to prevent dust from flying around.

[Hwang Kyung-wook/Director of the Asbestos Building Safety Management Association: Since the coating is applied or sprayed, it is a good method because it takes time and (asbestos) waste is not generated.]

We also need to consider the effectiveness of introducing coatings in addition to slate demolition.