The Takata air-bag recall already has affected the owners of almost 8 million vehicles, and U.S. Sen. Richard Blumenthal, D-Conn., continued to call for a national recall of those products and an overhaul of the National Highway Traffic Safety Administration, or NHTSA, on ABC’s “This Week.” Among those who have been advised to have their air bags replaced are the owners of certain BMW, Chrysler, Ford, General Motors, Honda, Mazda, Mitsubishi, Nissan, Subaru and Toyota models.

Blumenthal once again championed a national recall of the air bags made by the Japan-based automotive-parts manufacturer Takata Corp., saying the automakers must act in the public’s best interest. “The car companies here have a national responsibility here to support this recall,” Blumenthal said. The senator also pushed for an overhaul of the NHTSA that would encompass a change in culture at the agency.

Blumenthal and Sen. Edward J. Markey, D-Mass., wrote a letter to NHTSA cited by the New York Times Wednesday. In it, the legislators criticized the agency’s handling of the air-bag recalls, especially one involving the Toyota Motor Corp. Because of a shortage of replacement parts, the company advised some customers to disable their passenger-side air bags and avoid using those seats. The senators said those customers deserved access to free loaner cars while they awaited the repairs to their vehicles.

The U.S. Department of Transportation will conduct an investigation of NHTSA in the wake of the Takata air-bag recalls, ABC News reported. Defectively explosive air bags have been linked to three deaths and more than 100 injuries.

“Responding to these recalls, whether old or new, is essential to personal safety and it will help aid our ongoing investigation into Takata air bags and what appears to be a problem related to extended exposure to consistently high humidity and temperatures. However, we’re leaving no stone unturned in our aggressive pursuit to track down the full geographic scope of this issue,” NHTSA Deputy Administrator David Friedman said in a statement.