WASHINGTON, D.C. -

The U.S. Department of Transportation’s National Highway Traffic Safety Administration recently issued an amended order to continue the acceleration of recall repairs for millions of U.S. vehicle owners affected by the Takata air bag inflator recalls.

Officials explained the Amended Coordinated Remedy Order sets requirements for when automakers must have replacement parts available for customers and sets progress and completion deadlines for replacements of the defective parts which have been responsible for 11 deaths and approximately 180 injuries in the United States.

“The Department of Transportation is maintaining its aggressive oversight of the efforts to recall Takata air bags as quickly as possible,” U.S. Transportation Secretary Anthony Foxx said. “The amended order will speed up the availability of replacement air bags, and continues to prioritize the highest risk vehicles to protect the traveling public.”

NHTSA indicated the Amended Coordinated Remedy Order issued to Takata and the 19 affected automakers requires replacement parts to be obtained on an accelerated basis and made available first to the riskiest vehicles. The order sets new requirements for automakers to certify to NHTSA when they have obtained a sufficient supply of replacement parts to begin repairs, and requires automakers to coordinate consumer messaging using best practices identified by NHTSA, industry and the Independent Monitor of Takata and the Coordinated Remedy Program.

The regulator emphasized this action builds on the Coordinated Remedy Program initiated in November of last year, incorporating the additional tens of millions of inflators recalled or scheduled for future recall since that date, most of which were included in the May recall expansion.

“NHTSA is doing everything possible to make sure that there are no more preventable injuries or deaths because of these dangerous air bag inflators,” NHTSA Administrator Mark Rosekind said. “All vehicle owners should regularly check their vehicles for recalls at SaferCar.gov and go get them fixed at no cost as soon as replacement parts are available.”

Officials tabulated there are currently 46 million recalled Takata air bag inflators in 29 million vehicles in the United States. Under the Amended Consent Order issued to Takata in May, automakers will be required to recall additional inflators over the next three years, ultimately affecting approximately 64 to 69 million inflators in 42 million total recalled vehicles.

Ultimately all frontal Takata inflators using non-desiccated phase-stabilized ammonium nitrate (PSAN) will be recalled, according to NHTSA. The full list of vehicles that are currently affected or will be affected by future Takata recalls is available here.

Under the Coordinated Remedy Program, NHTSA has committed to seeking a 100-percent recall completion rate from the vehicle manufacturers to protect the motoring public. As of Dec. 2, automakers reported they have so far repaired approximately 12.5 million inflators.

Before establishing the schedule for the expanded Takata inflator recalls announced in May, NHTSA and its independent expert reviewed the findings of three independent research organizations into the Takata air bag ruptures and confirmed the findings on the root cause of inflator ruptures.

“A combination of time, environmental moisture and cycling high temperatures contribute to the degradation of the ammonium nitrate propellant in the inflators,” officials said. “Such degradation can cause the propellant to burn too quickly, rupturing the inflator module and sending shrapnel through the air bag and into the vehicle’s cabin.”

The regulator went on to stress the recall and remedy schedule mandated by NHTSA ensures that vehicles with defective air bag inflators are recalled and have replacement parts available before they present a significant risk to vehicle occupants.

“This is the largest and most complex safety recall in U.S. history,” officials said.

NHTSA has worked to increase consumer awareness of the recalls and encourage vehicle owners with open recalls to take action. The agency launched its Safe Cars Save Lives campaign in January, and conducted a five-state, 10-city bus tour —through the highest risk areas for Takata air bag ruptures — to find vehicle owners with open recalls and raise awareness of the SaferCar.gov VIN lookup tool.

The Takata recalls currently cover frontal inflators that do not include a chemical desiccant that absorbs moisture. There have been no reported ruptures of desiccated inflators due to propellant degradation.

Under the Amended Coordinated Remedy Order and the May Consent Order, Takata and automakers that use desiccated PSAN inflators are required to research their safety. Absent proof that the desiccated PSAN inflators are safe, they will also be subject to recall.

Officials added Takata is required to prove the safety of these inflators by the end of 2019.

Consumers can find complete information about the Takata air bag inflator recalls here.