A report by vehicle data provider Carfax says that though nearly 750,000 recalled Takata air bags were removed from vehicles on the road last year, 5.7 million others still have them.

The company said consumer awareness efforts by the Alliance for Automotive Innovation trade group, the federal National Highway Traffic Safety Administration and Carfax have helped lead to millions more replacements of defective air bags but that more work remains to address the many still in vehicles.

The recalled air bags can explode during deployment following long-term exposure to high heat and humidity, according to the NHTSA, which says the defective devices have caused injuries and deaths.

Carfax research found that five states have made the most progress in the past year to winnow the number of vehicles still on the road with the recalled air bags in place: California, Texas, New York, Illinois and Florida. Many of those same states, though, have the most outstanding air bag recalls: Texas, California, Florida, Pennsylvania and North Carolina.

The company offers to state motor vehicle and public safety agencies, vehicle inspectors and others free checks for unresolved recall repairs.

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