Toyota Motor Corp is recalling 7.4 million vehicles worldwide due to potential fire risks, the Japanese automaker said on Wednesday. The recall in the United States involves 2.5 million vehicles, related to 12 models, it noted. Toyota said that the driver\'s side Power Window Master Switch ( PWMS) may experience a \"notchy\" or sticky feel during operation. If commercially available lubricants are applied to the switch in an attempt to address the \"notchy\" or sticky feel, melting of the switch assembly or smoke could occur and lead to a fire under some circumstances. The sticky feel may be caused by an uneven application of the grease during the switch assembly process at the supplier. If the grease is not applied evenly, frequent use of the switch and normal operation may cause the grease to become carbonized and may eventually result in the deterioration of its lubricating properties, Toyota said. The company added that it will inspect and apply special fluorine grease to the driver\'s side PWMS. This is Toyota\'s largest recall since it recalled more than 10 million vehicles for unintended acceleration issues in the United States in 2009 and 2010.