Tokyo: The boss of Mitsubishi Electric resigned Friday after the Japanese electronics conglomerate admitted to tampering with some inspection data for more than three decades.

Earlier this week, the company said it improperly inspected some of its train car air conditioners and brake compressors. The oldest of the inspection documents produced was from 1985.

“I deeply apologize to everyone,” CEO Takeshi Sugiyama told reporters. “We have come to the conclusion that I have to step down as president and we have to work hard to regain confidence under new leadership,” he said.

Mitsubishi Electric is one of the largest manufacturers of general electricity in Japan, producing a wide range of products from household appliances to heavy machinery and defense equipment.

Trade and Industry Minister Hiroshi Kajiyama said the scandal could “seriously damage confidence in Japanese industry,” state broadcaster NHK reported.

Mitsubishi Electric has said it will conduct further investigations across all sectors, pledging to issue a report on the matter in September and take preventative action.

But he insisted that the affected products posed no safety risk.