The US International Trade Commission has determined that Chinese modules using Taiwanese components have caused injury to the US solar manufacturing industry.

The key vote means that trade tariffs set by the Department of Commerce in December will continue towards implementation unless a negotiated solution can be found between the two governments.

The case is a follow up to the 2012 investigation that put tariffs on Chinese PV modules. Many manufacturers began using cells produced in other countries, particularly Taiwan, in order to sidestep the new duties. Trade law specifies that a module’s origin is determined by where the cell is produced as this is the stage when “substantial transformation” takes place.

The new complaint, brought by SolarWorld Americas, has added Taiwan to the scope of the case. The Department of Commerce then took the step of broadening this scope. In effect, modules with Chinese assembly, wafers or cells would be classed as Chinese regardless of their origin.

The vote found 5-0 in terms of Chinese produce and 4-1 in the case of Taiwan.

“US companies, including SolarWorld, Suniva and Silicon Energy, thank the commission and its staff for its thorough investigation and fourth vote to uphold American trade laws,” said Mukesh Dulani, US president of SolarWorld

“Last night, in his State of the Union address, President Obama spoke about the need to promote the middle class, job creation and economic growth. American solar manufacturers have been doing their part by building or expanding facilities and hiring workers in states such as Oregon, Michigan, Ohio and New York.  This additional capacity will help us meet the need in the market for American-made solar,” he added.

Lawyers representing the Chinese manufacturers have argued that any product deemed Chinese ought to be included in the first trade case, meaning Chinese products should not be part of the second investigation at all.