The Alliance for American Manufacturing is a partnership of manufacturers like US Steel and their workers, represented by the United Steelworkers. They have sent a letter asking Commerce Secretary Locke to initiate investigations and use the currency discrepancy in complaints on specific imported products.
The background is that on March 31 a group of aluminum producers filed a "countervailing duty petition" with the Commerce Department. The department has until April 20 to decide whether to initiate an investigation. (There is a similar request pending for coated paper.) The letter urges the department to consider Chinese currency manipulation as a subsidy that is against trade rules.
China manipulates its currency, leading to a pricing advantage of as muc has 40%.
You may recall that in cases involving Chinese tires and steel products the Administration has imposed tariffs in response to unfair Chinese trade practices. Enforcing the tire case has already led to factories reopening and jobs returning.