TOKYO, Japan - Toyota, Honda, Nissan and Mazda are recalling a total of 3.4-million vehicles globally due to defective air bags supplied by Takata Corporation.The recall, the biggest since Toyota recalled more than seven million units in 2012, underscores the risk of huge global supply chain problems as automakers increasingly rely on a handful of suppliers for common or similar parts to cut costs.‘FIRE RISK, POTENTIAL INJURIES’Toyota is recalling about 1.73-million vehicles produced between November 2000 and March 2004, including 580 000 in the USA and 490 000 in Europe. There are no specific numbers yet for South Africa.Toyota reports that passenger air bags may not inflate correctly due to an issue with the propellant used. There was a risk of fire or passengers being injured because of the flawed inflators.Takata spokesman Hideyuki Matsumoto said the defect was caused by problems in the manufacturing process.The Japanese company supplies air bags and seat belts to major automakers, including Daimler and Ford.No injuries or deaths have been reported as a result of the faulty air bags. Toyota will replace faulty inflators, a fix expected to take one to two-and-a-half hours for most models.OTHER AUTOMAKER'S AFFECTED?Kohei Takahashi, an auto analyst at JP Morgan in Japan, said: "The inflators themselves are not so expensive but there is the cost to cover for the hours spent to fix the problem." Honda said it is recalling around 1.14-million vehicles, Nissan about 480 000 and Mazda 45 500 vehicles.Takata spokesman Hideyuki Matsumoto said the company estimated there were about two million vehicles using the defective airbag.