Amidst temperatures soaring past 30 degrees Celsius (86°F), bottled water is stacked outside a convenience store.

Touching it by hand, the water is warmed to the point of feeling hot.

It is the same at another nearby convenience store, where bottled water placed on outdoor display shelves is directly exposed to sunlight.

Measuring the temperature with a thermal imaging camera, the surface temperature rose up to 46°C (115°F).
This happens because there is a lack of space to store items inside the stores.

[Convenience store employee: Bottled water takes up space anyway and can cause inconvenience for movement (inside the store), so usually leaving everything outside is basically...]

[Chang Se-man / Climate and Environment Specialist Reporter: The problem is that when exposed to high-temperature direct sunlight in the midsummer like this for a long time, harmful substances to the human body can leach from the plastic bottles.]

As a result of an experiment conducted by the Board of Audit and Inspection four years ago, when bottled water was exposed to ultraviolet rays at 50°C (122°F) for 15 days, group 1 carcinogens such as formaldehyde and the heavy metal antimony were eluted.

This corresponds to the extent of storing them outside in natural conditions for 3.9 months, while actual bottled water is distributed for up to a year or so.

In the case of formaldehyde, there was no problem under domestic standards, but it exceeded the allowable limit under Japanese standards, and antimony, which lacks domestic standards itself, exceeded the allowable limit according to Australian standards.

When making plastic bottles, formaldehyde and other substances are generated in the process of applying high temperature and high pressure to plastic raw materials, and these flow into the bottled water when exposed to ultraviolet rays at high temperatures for a long time.

[Kang Sang-wook / Professor, Department of Chemical and Energy Engineering, Sangmyung University: When PET molecules are continuously exposed to ultraviolet rays, the (molecular) chains break, and the chemical substances generated in the process are aldehydes.]

The Ministry of Climate has revised the distribution and storage regulations for bottled water, making indoor storage mandatory starting tomorrow to prevent exposure to sunlight, and requiring covers to be placed if they are inevitably left outdoors.

However, considering circumstances such as a lack of storage space, the enforcement has decided to be deferred for two years, and controversy is expected as even the "mandatory use of covers" that could be applied immediately has been delayed.

Group 1 carcinogens detected but enforcement delayed by 2 years... Concerns grow over whether it is safe to drink (8 News, July 30, 2026)

Reported by Chang Se-man | Produced by Bae Jun-hwi | Video by Yu Mi-ra | VJ: Shin So-young | Produced by SBS Digital News