Radon risk returns as mattress safety lags

South Korea’s mattress industry is showing signs of complacency regarding radon gas safety certifications, despite a deadly scandal that rocked the nation in 2018. Radon is the second-leading cause of lung cancer after smoking.

According to the Korean Standards Association on Tuesday, Simmons — Korea’s top-selling mattress brand — remains the only company in the country to have obtained radon safety certification for its entire product lineup. Another popular mattress brand, Australia's Sealy, has also received certification from the agency, but its two flagship premium lines, the Haynes and Crown Jewel, remain uncertified.

In 2019, Sealy Korea recalled more than 350 products manufactured between January 2014 and November 2016 after the state-run Nuclear Safety and Security Commission detected radon — a Group 1 carcinogen classified by both the World Health Organization and the US Environmental Protection Agency. This followed the 2018 revelation that mattresses made by Korea’s Daijin Bed Co. emitted radon at levels far exceeding safety limits.

Although Sealy claimed that all of its products had since obtained radon safety certification, it faced public backlash in recent years when this was found to be untrue. In response, Sealy secured KSA safety certification for 92 products — excluding the two premium models — at the end of last year.

Sealy maintains that its Haynes and Crown Jewel lines have already met strict eco-friendly standards overseas. The company argues that since the KSA’s radon certification is voluntary and not legally required, there is no pressing need to certify its entire product line.

However, industry insiders argue that Sealy should take the issue more seriously, citing the ongoing fallout from the Daijin Bed scandal. Daijin effectively ceased operations in 2019, but out of approximately 280,000 radon-contaminated mattresses and related products, fewer than half — around 130,000 units — have been retrieved, according to sources.

“Even if Sealy holds international certifications, those don’t automatically apply in Korea,” said Cho Seung-yeon, an environmental engineering professor at Yonsei University. “There’s a reason why countries maintain their own standards. In Korea, where consumers remain particularly sensitive to the radon issue, trust is directly tied to obtaining domestic safety approval.”

Cho added that even if Sealy’s mattresses do not contain anion stones — such as monazite, the radioactive material used by Daijin Bed — all mattresses and bed frames are potentially susceptible to radon exposure. “Even wooden beds can be a source of radon if they use certain materials or construction methods that allow for radon infiltration,” he said.

Among other major mattress brands, Korea’s Ace Bed has not obtained radon certification since 2021. Meanwhile, companies like Tempur Korea, Sono Season and Allerman Spinks have yet to receive any radon-related approvals.

Emphasizing the need for stricter oversight, Cho said, “Developed countries have radon safety frameworks guided by organizations such as the US EPA and European regulatory bodies. Typically, local governments and private associations adopt these guidelines and develop their own systems, which are cross-verified to ensure proper implementation.”