WASHINGTON, May 20  -- The U.S. Commerce Department on Tuesday set preliminary subsidy rates on imported calcium hypochlorite from China, signaling that it may impose punitive duties on the products.

The department made its preliminary affirmative determination that Chinese producers and exporters of calcium hypochlorite received countervailing subsidy rate of 71.72 percent.

Punitive duties would be imposed after both the Commerce Department and the U.S. International Trade Commission (ITC) made affirmative final rulings, which are scheduled on Sept. 29 and Nov. 13, respectively. If the ITC makes a negative determination, the investigations will be terminated.

The U.S. Commerce Department launched the anti-dumping and countervailing duties probes over Chinese calcium hypochlorite products in January requested by Arch Chemicals based in the U.S. state of Georgia.

The company alleged that these 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.

Calcium hypochlorite is often used in the chlorination of water in residential and commercial swimming pools. Imports of these products from China were estimated at 8.1 million U.S. dollars last year, 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.