The investigation into malfunctioning airbags by the federal government has been expanded to include an additional 12.3 million vehicles. The investigation is focusing on the airbags inability to inflate in a crash, which could lead to death.

The faulty airbags, which are produced by ZF-TRW, a German auto component manufacturer, have caused as many as eight deaths, the Associated Press reported.

According to the National Highway Traffic Safety Administration (NHTSA), the problem that is causing the airbags to fail to deploy is with the control unit, which is supposed to sense when a crash occurs but may be having electrical interference by the crash impact itself.

The added 12.3 million vehicles in the investigation include cars manufactured by Honda, Hyundai, Kia, Mitsubishi, Toyota, and Fiat Chrysler.

If the investigation, which has been upgraded to a “engineering analysis,” proves widespread, the NHTSA may order a recall of the airbags affected. The NHTSA began it investigation a year ago, after becoming aware of six crashes that lead to four deaths and six injuries. At this time, the NHSTSA was looking into 425,000 vehicles.

This is not the first time that airbags have come under fire for their performance and operation. They are the source of frequent recalls, including one by Honda in March for 1.1 million vehicles that had a faulty inflator that caused the air bags to explode on impact.

The airbags were produced by Takata, which has created the largest ever automotive recall in the history of the U.S., NPR reported. The inflator in the airbag may fail to deploy as the chemical used to inflate the airbag can stop working if it is exposed to moisture or heat or if it is aged, Consumer Reports reported.

When the Takata airbags fail, they can spray shrapnel at the driver and passengers, which have led to the death of 16 people in the U.S. and at least 24 throughout the world with more than 300 people injured by the airbag explosions, according to the NHTSA.

Takata has also been a part of several lawsuits involving the malfunctioning airbags.

Takata Corporation (OTCPK:TKTDY) shares have lost more than 12 percent this year as the company prepares for a U.S. congressional hearing Tuesday. Wall Street is also eyeing stock movement from Apple Inc. (NASDAQ:AAPL), Fiat Chrysler Automobiles NV (NYSE:FCAU), Dollar General Corp. (NYSE:DG), Medtronic Plc (NYSE:MDT) and Youku Tudou Inc. (ADR) (NYSE:YOKU). Reuters/Rebecca Cook