Slag is the stony byproduct left over after smelting metal ores.
KAOHSIUNG, Taiwan (Sept. 21, 2025) — The Kaohsiung Environmental Protection Bureau (環保局) told the press that cleanup of steel converter slag at the Qishan District (旗山區) Dalin site (大林段) is ahead of schedule and on track for full removal by the end of 2026.
The Taiwan News explained that the project involves nearly 1 million metric tons of slag illegally dumped on farmland. Slag is the stony byproduct left over after smelting metal ores—in this case, steelmaking. When iron ore, limestone, and coke are melted in a blast furnace or converter to make steel, the impurities rise to the top and solidify into a hard, rocky material. That hardened waste is called slag (爐石 / zhǎo).
The dump site was first discovered in 2013 and, in 2017, a court ruled that it was industrial waste that required removal. Authorities said the company they deem responsible, repeatedly stalled the cleanup.
Following Chen Chi-mai (陳其邁) taking office as mayor in August 2020, the city canceled the previous cleanup plan and required the responsible firms to submit a new one. As of Sept. 19, 2025, the bureau says about 78% of the slag has been cleared, which puts the project slightly ahead of schedule. The city says the remaining material is expected to be fully removed and transported off-site by the end of 2026.
