A campaign to shut down furnaces that produce steel that fails to meet environmental and quality standards has created a 68 million-ton glut of scrap iron in China, said Seiichi Hayashi, head of Steel Recycling Research, a Japanese scrap iron research firm.

The export drive began in April, and as scrap found its way to Vietnam, one of Japan's largest markets for scrap iron, the Japanese industry was left to fret.

China's scrap iron exports spiked to 15,000 tons in April from a monthly average of 240 tons in the first quarter of 2017. They further skyrocketed to 80,000 tons in May and 510,000 tons in September. This compares with Japan's monthly average of 680,000 tons during the first 10 months of the year.

Concerns about the Chinese deluge temporarily pushed down scrap iron prices in Japan. But since Beijing regards scrap iron as an important resource, it levies a 40% export tax on the material, dimming prospects that China will start flooding markets with cheaper product in the near future.

"We are not overly concerned that Chinese exports may flood the Japanese market and cause prices to sink," said Kazuyoshi Aizawa, president of a scrap dealer in Kawasaki.

Tokyo Steel Manufacturing this spring did import Chinese scrap for its plant in Kyushu, in the south of the country.

For plants in Kyushu, which is close to China, this makes sense, said an executive at a steelmaker that uses electric furnaces in Japan's eastern Kanto region. But the company has no intention of following suit because transportation costs would offset the benefits, the executive added.

There are also concerns about the quality of Chinese scrap iron. "We cannot be 100% confident about the quality," said a manager in charge of purchasing at a blast-furnace steelmaker. "We have no plan to buy [Chinese scrap] no matter how cheap it is."

Attitudes are different in other Asian markets. In September, when Chinese scrap iron exports hit this year's monthly high for the first 10 months of the year, China exported 68,000 tons to Vietnam. Japan exported 129,000 tons to the country that month.

The figures alarm the Japanese industry because monthly Chinese exports to Vietnam were less than 10,000 tons until May and 20,000 tons in June.

Chinese exports can take land routes to Vietnam, which gives them a big advantage over those from Japan. "Offers for Japanese scrap iron from Vietnam have been decreasing," Aizawa said. "There is no doubt that Chinese exports are roiling Asian markets."

If Japanese exports decline due to Chinese competition, Hayashi of Steel Recycling Research said, domestic scrap prices will fall.