DETROIT — The U.S. government is trying to get automakers to move faster to fix 42 million vehicles that are being recalled because of potentially deadly Takata air bag inflators.

Expressing renewed concern about the pace of the recall, which is the largest ever for the U.S. auto industry, officials from the National Highway Safety Administration released a schedule for further recalls on Friday and said the agency would require all 19 companies involved to submit plans to reach more owners.

Eventually, about 69 million inflators that can potentially explode with too much force and spew shrapnel into people will be recalled. Some cars will have both the driver side and passenger side air bags replaced.

As of this month, however, only 12.5 million, or about 18 percent, of the inflators had been replaced, and NHTSA said some automakers weren’t doing enough to contact owners. The agency ordered the companies to turn in a “recall engagement plan” within 90 days.

Eleven people have been killed by Takata inflators in the U.S. and as many as 16 worldwide. The government says about 180 people have been hurt in the U.S. alone.

Recalls are being phased in through the end of 2020. NHTSA added sports car maker McLaren to the list of affected automakers.

NHTSA officials said the recalls have been proceeding slowly in part because of a lack of available parts. Different cars need different air bag inflators, so it’s not always easy to snap new parts into place.