WASHINGTON — Toyota first learned in 2008 about a defect in power-window switches that Wednesday prompted it to recall 7.43 million vehicles worldwide for fire hazards, according to documents filed with US regulators.

Toyota, based in Toyota City, Japan, received a report in September 2008 from the United States about an unusual smell from the power-window master switch and thermal damage to the switch, the company said in a report posted Thursday on the National Highway Traffic Safety Administration website.