WASHINGTON — Officials with the National Highway Traffic Safety Administration announced the launch of new investigations into rampant reports of noncrash fires and engine failures in Hyundai and Kia vehicles sold in the U.S. Affected vehicles include the 2011–’14 Hyundai Sonata, Hyundai Santa Fe, Kia Optima, and Kia Sorento, and 2010–’15-MY Kia Souls.

The probes follow the formal approval of a petition submitted by the Center for Auto Safety last June. NHTSA’s directors said analysts reviewed more than 3,100 reports of noncrash fires registered by consumers, more than 100 of whom claimed injuries, as well as data provided by the factories.

Much has changed since CAS’s petition was first submitted nearly a year ago. Federal prosecutors in the U.S. and South Korea have opened criminal investigations. Whistleblowers have emerged in both nations. Last month, Connecticut Attorney General William Tong announced his state was one of several investigating the OEMs over complaints of unfair and deceptive acts and practices relating to engine fires and failures.

Both manufacturers issued statements pledging openness and cooperation with ongoing investigations in response to NHTSA’s announcement. CAS’s Jason Levine said the probes are welcome but overdue.

“It is long past time for the full power of the federal government to be brought to bear to answer why so many thousands of Kia and Hyundai vehicles have been involved in non-crash fires. While it may be six months post-due, we are gratified to see NHTSA’s Office of Defect Investigations open formal investigations based on our petition,” a statement from the nonprofit’s executive director read, in part. “Hopefully, this step will quickly lead to a recall being issued as soon as possible. The reality is that extended investigations do not protect Kia and Hyundai owners — that requires recalls which result in effective repairs.”