GM again petitions NHTSA for exemption from Takata airbag recalls

The company claims many of its vehicles used a different inflator design that is not prone to failure.

General Motors has submitted another petition asking the National Highway Traffic Safety Administration to exempt many of its vehicles from the widespread Takata airbag recalls.

The company claims several airbag inflators used in its vehicles do not share the same problematic design traits that have caused other inflators to explode after long-term exposure to heat and humidity.

Northrop Grumman has been continuing an engineering analysis of the GM components, exposing the inflators to "extreme field exposure" equivalent to 35 years with "no ruptures" in the tests. The program has involved nearly 67,000 airbag deployments without experiencing a single rupture.

The study has "established that worse-than-worst case humidity exposure and temperature cycling will not cause inflator ruptures in the [GM vehicles] at any point within even unrealistically conservative vehicle-service life estimates."

GM says the inflators listed in the petition are not used by any other automakers and have "a number of unique design features that influence burn rates and internal ballistic dynamics, including greater vent-area-to-propellant-mass ratios, steel end caps, and thinner propellant wafers."

The automaker has submitted similar petitions in the past three years, however the latest filing includes more in-depth technical details from the Northrop Grumman study.

The inflators at the center of the petition were used in the 2010-2014 Chevrolet Silverado, Tahoe, and Suburban; GMC Sierra and Yukon; and Cadillac Escalade.

The NHTSA is still accepting public comment and has not yet made a decision on the petition.