It’s been revealed that Samsung Electronics used internal battery testing facilities to gain safety certification for its Note 7 smartphones.

Usually the trade organisation CTIA approves the safety standards that apply to phones sold in the US and tests devices for Apple Lenovo and Motorola.

In one of the costliest product safety failures in tech history Samsung recalled all 2.5 million Note 7s last month following reports of the phones catching fire.

As a result of the fires the US unit of Samsung is facing a proposed class action lawsuit from three Galaxy Note 7 customers alleging that despite the recall Note 7 owners continued to incur monthly device and plan charges.

Samsung has now set up booths at some of America’s busiest airports so travellers with Note 7s can exchange the devices on the spot or get a full refund. Passengers on all US carriers are banned from carrying Note 7s with airlines in Australia Europe and Asia doing likewise.