(Bloomberg) -- The U.S. is launching an investigation into whether Chinese solar-equipment manufacturers are evading tariffs by sending components to other Asian nations for assembly before shipping finished products to the U.S., according to the company that requested the probe.

The U.S. Commerce Department plans to take up the investigation, Auxin Solar Inc. said in a statement Monday.

“We are grateful Commerce officials recognized the need to investigate this pervasive backdoor dumping and how it continues to injure American solar producers,” the San Jose, California-based maker of solar equipment said.

The probe will focus on factories in Malaysia, Thailand, Vietnam and Cambodia, according to the Coalition for a Prosperous America, a trade group that supports U.S. manufacturing. The Commerce Department didn’t immediately respond to a request seeking comment. 

The investigation threatens to upend the U.S. solar sector, which depends heavily on Asian panels. Companies that build solar farms warn that simply opening a probe will drive up prices and potentially expose importers to retroactive duties. That could slow the growth of clean power in the U.S., undermining President Joe Biden’s goal to eliminate carbon emissions from the electricity sector by 2035.

Auxin says those warnings are fearmongering. 

First Solar Inc., the biggest U.S. manufacturer, rose as much as 7.4%. China-based JinkoSolar Holding Co., meanwhile, fell as much as 7%. Manufacturer Canadian Solar Inc. dropped as much as 6.9%.

The tariffs that Auxin says companies are evading date back to 2012, when the U.S. imposed duties on solar cells and modules from China under then-President Barack Obama after determining Beijing-backed companies were selling at cut-rate prices. Factories soon popped up elsewhere in Southeast Asia that produced solar cells and panels that weren’t subject to the tariffs.  

Auxin filed its request for the investigation in February, alleging that manufacturers in Malaysia, Vietnam, Thailand and Cambodia were using components from China and skirting the duties. It came after the Commerce Department in November rejected a similar request for an investigation by an anonymous group of U.S. solar companies.

Chinese firms dominate solar manufacturing, a multistep process that often occurs in separate factories that can be located in different provinces or even countries. 

LG Electronics Inc. said in February that it will cease operations at its U.S. solar factory as it exits the panel business -- a setback to Biden’s goal of boosting domestic clean-energy manufacturing.

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