In a securities filing submitted on Thursday, General Motors indicated that it may be required to recall an additional 4.3 million vehicles for faulty Takata airbag inflators. GM said that the call-back would cost the company $550 million.

In May, GM said that it would recall 1.9 million vehicles equipped with the defective inflators and expanded that number by 600,000 more vehicles in June after conducting a review of vehicle ownership information. GM has pegged the cost of repairing the 2.5 million vehicles at $320 million.

In a separate announcement, GM said that it would be recalling 307,000 2009 and 2010 model year Chevrolet Impalas globally because the airbags may not deploy in an accident. The company reported that seat frames in these vehicles may come in contact with electrical wires, causing the airbag fuses to short. The recall involves dealers applying anti-abrasion tape to prevent damage to the wires.

The Impala recall will affect close to 290,000 vehicles in the U.S. and 17,000 cars in Canada.