The United States confirmed steep import duties on Chinese chemicals used in sanitizing water on Tuesday after a complaint the products were unfairly subsidized and sold too cheaply in U.S. markets.

In its final decision, the Department of Commerce set anti-dumping duties of 210.52 percent on imports from China of calcium hypochlorite, used in chlorinating and sanitizing water, and anti-subsidy duties of 65.85 percent.

The companies the duties will hit include China Petrochemical International, a subsidiary of Sinopec Corp , Hubei Dinglong Chemical Co, Tianjin Jinbin International Trade, and Wuhan Rui Sunny Chemical Co.

The complaint was brought by Arch Chemicals. The United States imported an estimated $8.1 million worth of calcium hypochlorite from China in 2013.

The decision is subject to a final ruling from the U.S. International Trade Commission, which is due by Jan. 22 2015.