Takata inflators used in GM trucks and large SUVs are designed with different venting for hot gases released when the airbag deploys, and they are installed in the vehicle in a way that minimises exposure to moisture, GM said

Takata inflators used in GM trucks and large SUVs are designed with different venting for hot gases released when the airbag deploys, and they are installed in the vehicle in a way that minimises exposure to moisture, GM said

General Motors reportedly has said US regulators may force it to recall another 4.3m vehicles due to potentially defective Takata air bag inflators, at a cost of US $550m.

A Reuters report noted GM said in May it would recall 1.9m vehicles due to Takata airbag inflators that may not work properly and expanded this in June to another 600,000 vehicles after a review of ownership data.

GM reportedly said, in a securities filing, that the cost of replacing Takata inflators in the 4.3m additional vehicles would be $550m while replacing inflators in the 2.5m already-recalled vehicles would cost as much as $320m.

According to Reuters, GM has said it did not believe there was a safety defect in any of the 6.8m vehicles but agreed to the initial recall after talks with the National Highway Traffic Safety Administration (NHTSA).

In May, NHTSA said 17 automakers would be required to recall another 35m to 40m US airbag inflators assembled by Takata. Previously, 14 automakers had recalled 24m vehicles with 28.8m inflators linked to at least 13 deaths and more than 100 injuries.

GM said it believes that "the results of further testing and analysis will demonstrate that the vehicles do not present an unreasonable risk to safety and that no repair will ultimately be required."

GM had not begun making repairs on the initial 2.5m vehicles recalled nor yet accounted for the costs of the recall, according to Reuters.

GM reportedly said its Takata inflators have a unique design that does not pose a safety risk. The company said data showed no cases of an airbag rupturing among 44,000 deployments in large GM pickups and SUVs that contain Takata inflators.

Takata inflators used in GM trucks and large SUVs are designed with different venting for hot gases released when the airbag deploys, and they are installed in the vehicle in a way that minimises exposure to moisture, GM said.

But the Reuters report noted GM's stance was at odds with the position of regulators that all frontal Takata airbag inflators without a drying agent must be recalled.

NHTSA spokesman Bryan Thomas reiterated the agency's position. "The science clearly shows that these inflators become unsafe over time, faster when exposed to humidity and variations of temperature," he told Reuters.

The agency has now posted guidance on how automakers can petition for permission to alter the recall schedule but said the process should not be "used to eliminate a population of vehicles from the recall".