TOKYO, June 8 (Xinhua) -- Japan's Mitsubishi Materials Corp. admitted on Friday that it had mistakenly shipped products with a Japanese Industrial Standards (JIS) label when they did not meet the criteria.
The company said that its copper smelter and refinery in Kagawa prefecture in western Japan had inadvertently passed off copper slag products used to make concrete as meeting the JIS standards when they did not or relevant tests had not been conducted.
The plant's JIS certification has since been revoked due to the mistake between January 2015 and May 2018, according to Japan's Ministry of Economy, Trade and Industry.
The newly-found misconduct dealt a fresh blow to the diversified materials manufacturer, after it was hit last year when some of its subsidiaries were found to have manipulated inspection data.
Mitsubishi Materials Corp.'s quality scandal has highlighted an endemic problem in Japanese industries, with similar scandals also involving other major manufacturers here including Kobe Steel Ltd.
Automakers including Nissan Motor Co. and Subaru Corp. have also been under fire for using uncertified staff to carry out final vehicle inspections.