Several Taiwanese technology companies are helping Huawei Technologies Co. build infrastructure for an under-the-radar network of chip plants across southern China, an unusual collaboration that risks inflaming sentiment on a democratic island grappling with Beijing’s growing belligerence. On a scorching summer afternoon in Shenzhen in late August, one vast, nearly-finished construction site established by a Huawei-backed firm buzzed with workers. The dozens of hard-hatted staffers who gravitated toward nearby street vendors couldn’t be told apart except for brightly hued safety vests that bore their employers’ names and official logos. They included a unit of Taiwanese chip material reseller Topco Scientific Co. and a subsidiary of Taipei-based L&K Engineering Co., according to a Bloomberg News investigation. Across town at another Huawei-affiliated site, Bloomberg identified workers from a subsidiary of construction specialist United Integrated Services Co. Meanwhile, Taiwan’s Cica-Huntek Chemical Technology Taiwan Co. said on its website that it had won contracts to build chemical supply systems for two Chinese chipmakers — Shenzhen Pensun Technology Co. and Pengxinwei IC Manufacturing Co., which was blacklisted by the US last year. Both companies have been identified as working with Huawei to build chip fabrication facilities. The company removed the online reference after Bloomberg News inquired about it. The previously unreported Taiwanese presence in Huawei’s efforts risk triggering a backlash on an island that is preparing for polls next January, with the question of Taiwan’s rocky relationship with China likely the most pivotal issue.

Full investigation: Several Taiwanese tech companies are secretly helping Huawei build chip plants in southern China, an unusual collaboration with political risks.