The government is considering using Yongsan Park, a proposed green space planned for a former U.S. military garrison, as a site for new housing construction as it searches for ways to expand supply and contain surging home prices in Seoul — a political issue that is increasingly dragging down President Lee Jae Myung’s approval ratings.

The idea has pitted the central government against Seoul Mayor Oh Se-hoon, who says the site should be preserved as the city’s last major green space. But the government says the 3-square-kilometer site in central Seoul — roughly the size of Yeouido — could be used to expand the housing supply for younger people struggling to afford a home in the capital.

The government appears determined to press ahead with discussing redevelopment of the area. At a Cabinet meeting on Tuesday, Lee pushed back directly against Oh’s call for focusing more on redeveloping aging buildings, arguing that doing so could fuel speculative demand and trigger another sharp rise in home prices.

Speaking before the National Assembly’s Land Infrastructure and Transport Committee, Wednesday, Land Minister Kim Yun-duk said the government was examining whether housing development — particularly youth housing — could be possible on parts of Yongsan Park.

"There are areas — including officers’ quarters, military apartment complexes and the former Defense Acquisition Program Administration site — that have already completely lost their function as green spaces," he said.

This comes after Ha Joon-kyung, senior presidential secretary for economic growth, said on a radio show the same day that the administration saw the site as a "public asset" that should help young people establish stable lives, “get married and raise children.”

The state-owned site is among the few places where the government could pursue large-scale development without first acquiring land from existing residents, a process that takes years. If 30 percent of the site were designated for housing and developed at conventional urban density, it could, in theory, accommodate around 30,000 homes. If the government pursues a speedy supply, there is no better option in the crowded city.

The potential supply size could be even greater when combined with nearby development projects. Including planned housing at the Yongsan International Business District and Camp Kim, the broader area is estimated to be able to supply more than 40,000 homes — equivalent to more than half of the approximately 78,000 homes that were in Yongsan District as of 2023.

Legal, political, environmental hurdles remain

Yet there are still major legal and political hurdles to be addressed before anything can be done with the land. Under the current Yongsan Park Special Act, the site is to be developed as a national park. The ruling Democratic Party of Korea, which holds a majority in the National Assembly, is seeking to pass an amendment as early as Thursday that would allow separate development plans to be established for different sections of the park.

The government does not need formal consent from Seoul City or Yongsan District to press ahead with a redevelopment project. But forcing the plan unilaterally could invite a prolonged political standoff, as local officials could use their own planning, permitting and administrative powers to delay it.

Nearby residents have also spoken up, coming out against a plan to redevelop Yongsan Children's Garden. An Assembly public petition opposing housing construction at the park had drawn more than 18,000 signatures as of Thursday.

Oh said large-scale construction there would hurt the residents' quality of life. He said Seoul, though it looks green thanks to many hills and mountains, has only about 5.7 square meters of walkable neighborhood park space per resident — far less than in major cities such as London, New York and Paris, where comparable space is estimated to be four to six times greater.

“Housing is important, but as income levels rise, sufficient green space and parkland must also be secured,” he said Tuesday during a meeting with the district’s lawmaker, Rep. Kwon Young-se.

**Still returning, still contaminated **

The proposed park spans roughly 3 million square meters, according to the land minister. Yet only 768,000 square meters — approximately 25.6 percent of the total — has been returned since 2020. The remainder is still in U.S. hands, and most of it is empty.

The process had been slowed by the need to relocate remaining U.S. Forces Korea and Combined Forces Command facilities to U.S. Army Garrison (USAG) Humphreys in Pyeongtaek, Gyeonggi Province, which was completed in 2022. Only a few buildings remain active within USAG Yongsan, but the final completion date for the full return remains unclear.

Contamination presents another challenge, as well as who should bear the costs of cleanup. The site, used for military purposes by Japan and the U.S. for more than a century, is known to be contaminated with leaked petroleum and other chemicals that have seeped deep into the soil and groundwater.

Government surveys have found that benzene and petroleum hydrocarbons are present in parts of the site at concentrations hundreds of times above allowable levels. The full extent of contamination remains unclear. Investigations have largely been limited to the areas already returned, leaving the cost and timetable for cleaning up the entire site uncertain.

Presidential secretary Ha acknowledged the scale of the problem, saying that decontamination could cost anywhere from hundreds of billions of won to more than 1 trillion won ($721 million).

He argued that housing development could make the cleanup easier to justify, because construction would require contaminated soil to be excavated and removed anyway.