TOKYO — Another pillar of Japanese industry admitted falsifying quality data on Tuesday, as Toray Industries Incorporated, a manufacturer of materials like carbon fiber, said one of its subsidiaries had for years been providing clients with false product-test reports.
The subsidiary, Toray Hybrid Cord, makes cord-like materials used to strengthen car tires and other objects. Toray said it had identified 149 instances in which Toray Hybrid Cord altered data after internal tests showed its cords failed to meet manufacturing standards demanded by customers.
Toray said it had sold products with falsified test data to 13 customers. It declined to name those customers but said the deception did not involve parts supplied to Boeing, to which Toray is an important provider of lightweight carbon-fiber components used in aircraft bodies.
The deception, which Toray said took place between 2008 and 2016, echoed similar practices admitted in recent weeks by Kobe Steel and Mitsubishi Materials. Together, the revelations have embarrassed a country that has built its economic reputation on reliable, high-quality manufacturing.
The revelations appear to be creating a kind of snowball effect. Toray said it became aware of the problem in July 2016 but had not disclosed it widely because there was no threat to public safety. Toray Hybrid Cord’s products met basic safety standards, Toray said, so the car tires and other items that incorporate them do not need to be recalled or replaced.
But Toray’s chief executive, Akihiro Nikkaku, said Toray decided to go public in part because of the added scrutiny and the pressure created by the Kobe Steel and Mitsubishi Materials disclosures.
He added that partial information about the Toray Hybrid Cord issue had begun to leak online, posted by anonymous sources that he presumed to be Toray employees, and that the leaks had helped to force Toray’s hand.
“Rather than have it come out as rumor we thought it was better to announce it publicly,” Mr. Nikkaku said at a news conference on Tuesday.
Toray’s share price fell more than 5 percent on Tuesday.
While Toray is not a well-known name outside Japan, its importance to the global supply chain and its influence in Japan are considerable. Growing demand for carbon fiber from a range of industries has turned Toray into a crucial supplier for many companies. Its former chief executive, Sadayuki Sakakibara, is now the chairman of Keidanren, the influential business organization that lobbies on behalf of Japan’s largest companies.
On Monday, before Toray’s revelations, Mr. Sakakibara warned at a news conference that deceptive quality-reporting practices by Japanese companies threatened to undermine trust in the nation’s manufacturing.
“It’s a grave situation,” Mr. Sakakibara said, adding that any discrepancies between the actual and promised specifications of a manufactured product “should in principle be made public as soon as they are discovered.”
Manufacturers often ask suppliers to produce components to even higher specifications than legally required. Like Kobe Steel and Mitsubishi Materials previously, Toray said that when quality inspections revealed that products from Toray Hybrid Cord fell short of those standards, workers sometimes faked inspection data to make it appear as though the products met them. No deaths or product failures have been attributed to the false data.
Japanese carmakers have also been hit by revelations that they cut corners in their quality controls. Nissan and Subaru acknowledged last month that they had been allowing workers who lacked certifications required by Japanese regulators to inspect vehicles produced for the Japanese market.