TOKYO — Mitsubishi Materials revealed Thursday that inspection data was falsified at a total of three subsidiaries, with at least 258 customers potentially receiving parts below their quality specifications.
The Japanese company plans to hold a press conference Friday to explain the improprieties at Mitsubishi Cable Industries, Mitsubishi Shindoh and Mitsubishi Aluminum.
Mitsubishi Cable mainly falsified measurement data at its Wakayama Prefecture plant for O-rings, a rubber material used as a seal to keep out oil, water and other liquids. O-rings are used in a wide range of fields such as airplanes, industrial machinery and automobiles. The company has finished briefing 40 out of 229 clients that possibly received shipments of substandard products.
The problem was discovered in February after Mitsubishi Materials performed quality inspections last December. But Mitsubishi Cable did not report the matter to its parent until October, when similar problems at Kobe Steel probably forced it to go public with the information, some in the industry say.
Nonferrous metals maker Mitsubishi Shindoh tampered with data concerning the hardness and tensile strength of copper products used in electronic devices and terminals for cars at its Fukushima Prefecture plant. The company has explained the situation to 14 out of 29 customers that may have received these items.
Mitsubishi Aluminum also shipped products that were not up to specifications but says it has already finished safety checks for all the customers involved. The company did not reveal the number of clients, products or shipment value affected.
All three subsidiaries appear to have abused a business practice known as tokusai, whereby clients can consent to accept products that do not fulfill agreed-upon standards. The Mitsubishi Materials’ units continued to ship the substandard products, believing that no complaints meant no problems. But most companies tend to inspect only the first shipments they receive. After that, “we trust the materials makers and just check the documents,” admitted one major automaker.
No safety concerns or regulatory infractions have been confirmed at this time, but the misconduct is reminiscent of Kobe Steel’s recent data scandal and is likely to reignite questions into corporate Japan’s quality controls.
Mitsubishi Materials is a major nonferrous metals company handling a variety of business lines that include copper, cement, hard-metal tools and electronic material. Mitsubishi Cable booked sales of some 29.5 billion yen ($265 million) for the year ended in March, while Mitsubishi Shindoh saw sales of roughly 122.5 billion yen.