Bankrupt module manufacturer Suniva’s petition before the U.S. International Trade Commission (ITC) just got an enormous shot in the arm, as SolarWorld Americas has joined the complaint as a co-petitioner.

The news comes two days after the ITC agreed to launch an investigation to “determine whether crystalline silicon photovoltaic (“CSPV”) cells (whether or not partially or fully assembled into other products) are being imported into the United States in such increased quantities as to be a substantial cause of serious injury, or the threat thereof, to the domestic industry producing an article like or directly competitive with the imported articles.”

Juergen Stein, president of SolarWorld Americas, said his company had no choice but to join Suniva’s complaint to protect U.S. solar manufacturing jobs.

“We have hoped and waited for serious proposals for settling the overall U.S. solar industry’s trade tensions with China, but we have received none,” Stein said. “Therefore, we have decided to join the case to pursue the best remedy available to us to restore fair competition in the U.S. market.”

“The U.S. solar industry cannot afford to give away the future of critical renewable-energy manufacturing industries,” Stein continued. “We must take a stand in favor of preserving intellectual property, production know-how and U.S. manufacturing jobs, all of which have sprung from a vital industry pioneered on U.S. soil since the 1970s.”

Some industry observers expressed surprise at SolarWorld Americas’ decision, given that it had previously reacted coolly to Suniva’s petition. In a statement to pv magazine, the company said it changed its mind after seeing what it called an import surge that has seriously injured the U.S. industry.

“We look forward to working with Suniva to prosecute and win this case,” said Tim Brightbill, a partner with Wiley Rein LLP and trade counsel to SolarWorld Americas. “We will also urge the [Trump] Administration to impose a remedy that preserves solar manufacturing in the United States while maintaining strong solar demand and strengthening the U.S. supply chain.”

For Suniva, SolarWorld’s support is an enormous boost for the petition, which has been roundly criticized throughout the industry as being potentially destructive. One IHS Markit study suggested that the U.S. PV module market could contract as much as 60% by 2021.

Suniva said it appreciated SolarWorld’s support in what is says is a battle to save module manufacturing in the United States.

WARN Act notices are required to be given by companies with more than 100 employees at least 60 days in advance of mass layoffs or plant closures. It is notable that a number of the other solar companies who recently had mass layoffs did not provide WARN Act notice to their employees.

(One of the companies that did not provide WARN Act notices to its employees was Suniva, when it closed its Michigan manufacturing plant and severely cut staff at its Georgia headquarters. There is a civil lawsuit currently pending against the company for those alleged violations.)

It’s also worth noting that this is not SolarWorld’s first time being involved in a trade dispute with Chinese manufacturers. In 2011, the company filed a petition alleging the Chinese manufacturers were dumping panels on the U.S. market at below the cost of manufacture. SolarWorld’s petition did result in tariffs being imposed on Chinese manufacturers.

Update: This article was updated at 7:13 pm EST on 5/25/17 to incorporate comments from Tim Brightbill, a partner with Wiley Rein LLP and trade counsel to SolarWorld Americas, regarding SolarWorld Americas’ decision to join the Suniva trade action after initially expressing reservations about it.