At a time when toys, televisions and other products made in China are flooding into the United States, helping push the trade deficit to record levels, there is at least one American product for which China has a nearly insatiable demand -- industrial junk.

Sales of scrap metal to China have surged, with effects that are ricocheting across the American economy. Prices are soaring not just for scrap, but for metals in general. After years of surpluses that forced many steel makers into bankruptcy, supplies are so tight that contractors told a Congressional hearing in Washington this week that they sometimes cannot obtain supplies at any price.

China last year became the first country ever to import more than $1 billion of American scrap, according to the newspaper American Metal Market. Indeed, it would not be an exaggeration to say that China's transformation into an industrial powerhouse is being fueled by America's waste, and that of other countries, as well. Much of the material being used to build China's skyscrapers, factories and telecommunications systems -- along with many of the products it exports -- is derived from scrap, which is usually cheaper than new metal made from ore.

''China is very hungry,'' said David Pan, a Chinese-born scrap metal buyer, as a truck carrying steel reinforcing bars from a dismantled building in San Diego prepared to dump its cargo with a deafening clatter on the floor of his warehouse in Maywood, an industrial town just south of here. ''They need a lot of material.''