The U.S. International Trade Commission will launch an investigation in September into 33 steel products for a possible emergency curb on imports, including those from Japan, an industry source said Wednesday.

The ITC, an independent federal agency, plans to begin the investigation with four days of hearings starting Sept. 17. At least one of the hearings is to be held in steel mill country, such as Cleveland and Gary, Ind., the source said.

It is unusual for the ITC to hold a hearing outside Washington, where its headquarters are located.

The administration of President George W. Bush asked the ITC in June to launch an investigation under Section 201 of the 1974 trade act to decide whether increased steel imports are hurting the U.S. steel industry.

The investigation could result in emergency measures, such as imposing higher tariffs or import quotas, which steel industry and labor union leaders have been lobbying the administration to introduce.

The Bush administration's investigation request covered all four steel categories -- flat products, long products, pipe and tube, and stainless steel and alloy tool products.

The industry source said the ITC, in response to the administration's request, decided to target 33 items, covering almost all steel products under the four categories.

Representatives from U.S. steelmakers, labor leaders and local members of Congress are scheduled to speak at the hearings, while steel industry workers are expected to stage demonstrations. outside calling for tough measures against imports of foreign steel products, the source said.

Steel-exporting countries will argue their products are not hurting the U.S. industry and ask U.S. users, including automakers, to testify on their behalf, the source said.