Calcium hypochlorite is an ingredient in bleaching powder, widely used for the disinfection of drinking water or swimming pool water.

　　The investigations are in response to a petition filed by Arch Chemicals based in Georgia, the department said in a statement.

　　The company alleged that calcium hypochlorite products from China were sold below the fair value of the products in the U.S. market with dumping margins of 182.51 to 210.52 percent, while Chinese producers and exporters also received government subsidies.

　　The International Trade Commission (ITC), the U.S. trade authority, is scheduled to make its preliminary inquiry determination around Feb. 3.

　　The probes will continue if the ITC determines that the imports of calcium hypochlorite from China "materially injure or threaten the domestic industry of the United States." The U.S. Commerce Department will then make its preliminary determination of CVD and AD in March and May, respectively.

　　Imports of calcium hypochlorite from China were estimated at 7 million U.S. dollars in 2012, according to U.S. official data.

　　Beijing has repeatedly urged Washington to abide by its commitment against protectionism and work with China to maintain a free, open and just trade environment.

　　China filed a complaint last month under the WTO's dispute settlement mechanism over anti-dumping measures by the United States against 13 types of Chinese products.

　　"In its anti-dumping investigations and reviews, the U.S. has inappropriately applied targeted dumping methodology, denied companies separate tax rates, and used unfavorable facts," Chinese Commerce Ministry Spokesman Shen Danyang said in a statement issued last month.

　　China is resolutely against the misuse of trade remedy rules and protectionism and will determinedly maintain its rights as a WTO member and safeguard the interests of domestic industries, he said.