What's holding your building up? Chinese steel?

Two years ago Canada and the United States imported almost no steel from China. In the first six months of 2007, however, steel imported from China to North America constituted 102,000 metric tons.

That may pose more of a problem than just the economic damage done to North American steel producers. Steel being used domestically in China's building boom has been found to be up to five times lighter than the weight required to be used in construction.

HALF the steel material sold at wholesale markets and now being used in construction has failed quality tests.

The Shanghai Industrial and Commercial Administrative Bureau inspected 52 batches of steel material at three markets and 15 construction sites in seven districts, including Xuhui, Zhabei and Baoshan, and officials said 27 batches had quality problems.

The tested materials were too light to reach the country's standard - some of the products were five times lighter than the required weight.

About 22 percent of the tested products failed tension tests. Buildings with such steel would not be able to withstand major earthquakes, the bureau said.

Forty-eight percent of the tested material had inadequate amounts of carbon. Shortage of carbon can cause steel to break easily, officials explained.

One good earthquake could bring Shanghai down.

OK. So, aside from the fact that it will devastate Shanghai, what does that have to do with North America?

A lot.

Tim Johnson of the McClatchy Beijing bureau picked up on the problem of weak Chinese steel being exported to North America last September.

Steel imports from China that fall apart easily are making U.S. manufacturers and constructions firms more than a little nervous. Reports of failures during initial fabrication and questions about certification documents will mean closer scrutiny. The American and Canadian institutes of steel construction have already advised member companies to be vigilant and report any problems.

The biggest concern is hollow structural sections widely used in construction of skyscrapers, bridges, pipelines, office, commercial and school buildings. This high-strength steel is also commonly used in power lifts, cranes, farm equipment, furniture and car trailer hitches.

Chinese high-strength steel tubes and pipes are also a potential problem. They’re used extensively in power plants and in large industrial boilers, and must withstand enormous pressures and hellish heat around the clock for weeks or months on end. This kind of steel also is used extensively in scaffolding that's erected on building exteriors during construction or renovation, as well as for interior work.

Inferior high-strength steel could cause catastrophic failures of buildings, pipelines or in power plants' boiler tubing. This is a large worry for structural engineers who will be working overtime as states embark on what amounts to a crash program to shore up bridges, following the collapse of the Minnesota span over the Mississippi River. China is already seeing problems. A Chinese power plant exploded recently when high-strength steel tubing blew out, says Roger Schagrin, general counsel for the Committee on Pipe and Tube Imports, which represents U.S. manufacturers of these products.

As steel producers across North America bring their plants to an idle while their product is replaced by the cheaper Chinese-produced steel, an old adage rises as a reminder: You get what you pay for.

Something to keep in mind when you're driving over that refurbished bridge.