The recalls apply to a number of Subaru models released between 2003 and 2014 that have Takata airbags in the front passenger seat. These can explode when deployed and send sharp metal fragments flying, which could seriously injure or kill the driver or passengers.
The driver's seat front airbag is not in danger of explosion, Subaru said.
The same crop of cars were recalled in 2015 for the same reason, though their airbag inflators were replaced with the same defective Takata design then, the National Highway Traffic Safety Administration (NHTSA) said.
The Subaru models join "tens of millions" of vehicles with Takata airbags recalled again, the safety agency said.
The inflators could explode when the propellant that triggers the airbags degrades after many years of exposure to "high absolute humidity" -- the amount of water vapor in an air sample -- high temperatures and toggling between extreme heat and extreme cold, the NHTSA said.
What to do
Subaru should notify all owners whose cars are affected by the recall. Local Subaru dealerships will replace all passenger air bag inflators for free with an appointment, and the repair should take about three hours, the company said.
Owners can also contact the Subaru recall team at 888-575-1382 or look up their vehicle identification number (VIN) with NHTSA to check whether their vehicle is subject to recall.
Parts are available for repairs now, but this could change due to the number of vehicles affected. Subaru warned passengers not to ride in the front passenger seat of affected vehicles until they're repaired.