A contractor of a Mitsubishi Heavy Industry Ltd. subsidiary intentionally released ozone-depleting gas chlorofluorocarbons into the air at a Mitsubishi facility in the town of Miwa, Aichi Prefecture, Mitsubishi Heavy officials revealed Saturday.
The incident came to light after an anonymous phone call tipped off Mitsubishi Heavy Industry on Tuesday.
The repair company, commissioned by the subsidiary to fix air conditioners, released 63 kg of CFC into the air over a period of about one month from July 8, the officials said. The CFC had been collected from air conditioners.
The officials said the repair company released the gas after bungling the collection process by, for example, failing to have a sufficient number of gas cylinders ready to accommodate the gas.
The repair company asked the Mitsubishi subsidiary about potential problems prior to the operations, according to the officials, but the subsidiary failed to make a specific response.
A Mitsubishi Heavy Industry spokesman admitted the subsidiary's response to the repair company was inadequate and pledged to take preventative steps.