Tens of millions of vehicles are on the roads with faulty airbags and the problem appears to be growing.

The National Highway Traffic Safety Administration in the US says that between 70 million and 100 million vehicles may have the fault and to date only a fraction have been fixed. Meanwhile Toyota has announced it is recalling a further 5.8 million cars over potentially faulty air bag inflators, including those used as replacement parts following a 2010 recall.

The issue concerns an inflator made by specialist supplier Takata. If faulty the airbags’s inflator, can ignite and shooting metal shards into the vehicle. The fault has been linked to 16 deaths reported worldwide and more than 100 serious injuries. Vehicle makes affected include; Audi, BMW, Ford, Honda, Mazda, Mercedes-Benz, Mitsubishi, Saab, Subaru, Toyota and Volkswagen.

The problem appears to be much worse in countries with hotter climates as a chemical compound in the inflator becomes unstable.

Toyota's latest recall includes the Corolla and Yaris and covers both driver-side and passenger-side airbags installed in cars produced between May 2000 and November 2001, and April 2006 and December 2014.