Bangkok, March 31, 2025 – Test results from 28 steel samples recovered from the wreckage of the collapsed State Audit Office (SAO) building in Bangkok’s Chatuchak district have revealed that two failed to meet required standards, according to Nonthichai Likitaporn, director of the Thai Industrial Standards Institute (TISI)’s Standards Division 1. The findings mark a turning point in the ongoing investigation into the collapse, which occurred on March 28 following a powerful earthquake centered in Mandalay, Myanmar, approximately 392 kilometers from Thailand’s Mae Hong Son province.
The 33-storey SAO building, still under construction at the time of the collapse, was intended to serve as the new headquarters for Thailand’s auditing authority. The disaster claimed at least multiple lives, injured dozens, and left scores of workers missing, with rescue operations continuing into Monday evening. The structure, valued at 2.13 billion baht (approximately $63 million USD), was being built by a partnership between a Thai and Chinese company.
Nonthichai’s announcement has intensified scrutiny on Xin Ke Yuan Steel Co., Ltd., previously identified as the supplier of the deformed steel bars used in the building’s construction. Earlier this year, in January 2025, the Ministry of Industry charged Xin Ke Yuan Steel with producing substandard steel following an inspection of its factory in Ban Khai, Rayong. That investigation, prompted by a fire incident late last year, uncovered multiple safety and environmental violations, as well as evidence that the company’s steel failed to meet critical strength standards. Authorities seized stock and collected samples at the time, with test results confirming deficiencies that could compromise structural integrity.
“We’ve tested 28 samples so far, and two did not meet the standards set by TISI,” Nonthichai said during a press briefing on Monday. “This is a preliminary finding, and we will be collecting additional samples from the site to conduct a more comprehensive analysis.” He added that the investigation remains ongoing, with experts working to determine whether the substandard steel directly contributed to the collapse or if other factors, such as construction practices or the earthquake’s intensity, played a larger role.
The SAO building’s collapse has raised many questions about construction quality and oversight in Thailand, particularly given that it was the only structure in Bangkok to fail completely during the earthquake.
Industry Minister Akanat Promphan, who has taken a hardline stance on substandard materials, reiterated on March 31 that any manufacturer found responsible for supplying defective steel would face severe consequences. “If it’s confirmed that substandard steel was used, the factory will be shut down, their industrial standard certification revoked, and their steel recalled,” Akanat stated. “Legal action will follow.”
The collapse has also drawn international attention, with the Chinese Embassy pledging cooperation in the investigation. China Railway Number 10, a subsidiary of the state-owned China Railway No. 10 Engineering Group, holds a 49% stake in the ITD-CREC joint venture—the maximum foreign ownership allowed under Thai law.
On March 30, Chinese Ambassador Han Zhiqiang met with Thai Interior Minister Anutin Charnvirakul, accompanied by disaster-management experts, to discuss the incident. The ambassador expressed condolences and assured Thai authorities that the contractor would assist fully, though several Chinese nationals linked to CREC were detained the same day after attempting to remove documents from the site, claiming they were needed for insurance purposes.
As rescue efforts continue, with heavy machinery and sniffer dogs deployed to locate survivors, the Thai government has set a seven-day deadline for an initial probe into the collapse. Interior Minister Anutin, overseeing the rescue operation, stressed that the investigation would first verify whether the building’s design met earthquake-resistance standards mandated by law. “If the design is sound, we’ll look at the materials and construction processes,” he said. The committee, comprising engineers from the Department of Public Works and other experts, aims to deliver findings by April 6.
