CHICAGO: US trade officials on Monday said they will launch an investigation into whether to impose tariffs on solar energy equipment from four Southeast Asian nations, a blow to project developers that rely on cheap imports to keep their costs down.

The decision is a victory for Californian solar manufacturer Auxin Solar, which requested the probe. Its petition is the latest in a string of efforts by US solar producers to stem the flow of cheap Asian panels that dominate the market.

San Jose-based Auxin earlier this year requested an investigation by the department, arguing that Chinese manufacturers shifted production to Malaysia, Thailand, Vietnam and Cambodia to avoid paying US duties on Chinese-made solar goods.

In a memo on a Commerce Department web site, officials said Auxin had provided information indicating that solar companies operating in Malaysia, Thailand, Vietnam and Cambodia are subsidiaries of large Chinese producers and that products made there would be subject to US countervailing and anti-dumping duties if made in China.

“Auxin properly alleged the elements necessary for a circumvention determination,” the memo said.

Commerce will issue a preliminary determination within 150 days, it said.

Auxin welcomed the decision. “We are grateful Commerce officials recognized the need to investigate this pervasive backdoor dumping and how it continues to injure American solar producers,” Auxin Chief Executive Mamun Rashid said in a statement.