By Keith Laing - 04/08/14 01:05 PM EDT
An automobile safety group is pushing federal regulators to launch an additional investigation into General Motors.
The Washington, D.C.-based Center for Auto Safety said in a letter to the National Highway Traffic Safety Administration (NHTSA) that the performance of airbags in GM's Chevrolet Impala vehicles should be investigated.
The request comes as GM is under fire for its handling of a dangerous ignition switch flaw that has been found in more than one million of its vehicles. GM CEO Mary Barra came under tough questioning from House and Senate lawmakers at a pair of hearings about the issue last week.
The Center for Auto Safety said that there were 143 frontal impact fatalities in model year 2000 to 2010 Chevrolet Impalas where airbags failed to deploy. Ninety-eight of the fatalities were wearing lap and shoulder seat belts, the group said in its letter to Acting NHTSA Administrator David Friedman.
"We call on NHTSA to examine each of the fatal non-deployment crashes to determine whether the airbag should have deployed and why it didn't," the letter from Center for Auto Safety Executive Director Clarence Ditlow said.
The highway safety agency has been criticized by lawmakers for failing to properly oversee GM's handling of reports about safety problems.
The GM ignition switch recall involves 1.6 million cars that are mostly older models that the company no longer makes, such as Chevrolet Cobalts and Saturn Ions. GM has also issued another recall of 1.3 million cars that had a faulty power steering mechanism in the midst of the firestorm about the ignitions.
The highway safety agency has blamed GM for not providing accurate information about its testing of the ignitions switches to regulators.
The Center for Auto Safety said the agency could have also been too slow to regulate GM's handling of the Impala airbags.
"The Center is deeply troubled that NHTSA once again may have missed an advanced airbag like it did with the Cobalt," Ditlow wrote. "The Center is even more troubled that once again NHTSA has kept whatever it is doing secret behind closed doors even though there is a specific legal requirement for NHTSA to make its activities public."
The NHTSA said in a statement that provided to The Hill that is "evaluating" launching the investigation that is being called for by the auto safety group.
“NHTSA has received and is evaluating a petition about possible defects in the occupant classification system in certain Chevrolet Impalas," the highway safety agency said. "The agency will respond to the petitioner directly.”
The full CAS letter on the request for a Chevrolet Impala airbag investigation can be read here.
-This story was updated with new information at 2:39 p.m.