(Adds reaction from aluminum producers group)
WASHINGTON, Dec 7 (Reuters) - The U.S. International Trade Commission said on Friday it made a final determination that American producers were being harmed by imports of common alloy aluminum sheet products from China, a finding that locks in duties on the products.
The ITC determination means that duties ranging from 96.3 percent to 176.2 percent previously announced by the U.S. Commerce Department would be put in place for five years.
The department said last month the products were being subsidized and dumped in the U.S. market.
The decision marked the first time that final duties were issued in a trade remedy case initiated by the U.S. government since 1985. Usually, trade cases are launched based on a complaint from a U.S. producer or group of producers.
The Trump administration has promised a more aggressive approach to trade enforcement by having the department launch more anti-dumping and anti-subsidy cases on behalf of private industry.
There were contrasting reactions from trade organizations for aluminum producers and the recreational boating industry to the ITC move.
The decision "provides much-needed certainty and confidence to U.S. common alloy sheet producers, allowing them to invest, grow, and add jobs to the US economy," Aluminum Association President and Chief Executive Heidi Brock said in a statement.
The National Marine Manufacturers Association criticized the measure and urged the administration to "to back off their tariffs first trade policy."
"Boat builders are seeing a 30 to 40 percent price increase for aluminum sheet, even though the vast majority source the material domestically. In addition, the compounding tariffs on Chinese aluminum sheet have strained the global supply, making it difficult for our industry to find enough aluminum sheet to keep up with manufacturing demand," it said.
In 2017, imports of common alloy aluminum sheet from China were valued at an estimated $900 million. The flat-rolled product is used in transportation, building and construction, infrastructure, electrical and marine applications.
U.S. aluminum industry firms, including Aleris Corp , Arconic Inc and Constellium NV, testified in the case last year about what they termed a surge in "low-priced, unfairly traded imports." (Reporting by Timothy Ahmann; Editing by Mohammad Zargham and Tom Brown)