Expanding their investigation beyond Takata-made airbags, the National Highway Traffic Safety Administration (NHTSA) has launched an inquiry into airbag inflaters made by ARC Automotive. The investigation was announced Tuesday on the NHTSA’s website, explaining that the airbag inflaters are utilized in more than 400,000 model year 2002 Chrysler Town and County minivans, as well as approximately 70,000 Kia Optimas.

Investigations into this company follow reports of two separate airbag ruptures–one in 2009 involving a Town and Country minivan and the other in 2014 involving a Kia Optima–with both drivers suffering injuries. The inflaters in the airbags in question also utilize the same explosive compound that is present in recalled Takata airbags. So far, Takata has recalled more than 34 million inflaters, affecting vehicles made by 11 different automaker in the U.S. alone.

The ARC Automotive airbag inflaters, like those made by Takata, utilize ammonium nitrate to help create the gases that will inflate an airbag. However, investigations into Takata airbags have revealed that this compound can break down over time, and in doing so, can become highly combustible.

A spokesperson for Fiat Chrysler stated that the auto manufacturer no longer uses the inflater model that is under investigation.