Almost all models occasionally burst into flames for one reason or another, but there’s too many older Kia and Hyundai models catching fire to write it off as a statistical inevitability, the Center for Auto Safety says.

In a letter sent to the National Highway Traffic Safety Administration on Monday, the nonprofit advocacy group used owner-submitted questionnaires from the NHTSA’s own website as proof that something’s amiss with certain 2011-2014 Kia and Hyundai models. 120 reported vehicle fires and 229 cases of melted wires in the engine compartment, smoke, or burning odors should be enough to spark an investigation, CAS said.

The letter sent to NHTSA deputy administrator Heidi King (first reported on by Automotive News) singles out four models, all from the 2011 to 2014 model year: the Hyundai Sonata and Santa Fe Sport, and Kia Sorento and Optima.

The fires reported to the federal agency were non-collision related blazes, sometimes breaking out hours after the owner parked the vehicle. In total, the VOQs submitted to the NHTSA reveal 33 blazes for the Optima, 30 for the Sorento, 10 for the Santa Fe Sport, and 47 for the Sonata.

“The vast majority of complaints which discuss the origins of the vehicle fires state that smoke and/or flames are first seen emanating from the engine bay, then the car is quickly engulfed,” wrote CAS executive director Jason Levine in his petition.

Each vehicle shares Hyundai Motor Group’s Y platform and many associated powertrain components, and all but the Sonata were built at the same assembly plant in West Point, Georgia. The Sonata was assembled in Montgomery, Alabama. While the cause of the individual fires isn’t known, CAS worries it’s related to the manufacturing process or a supplier error. It wants the NHTSA to funcover the cause and, if necessary, issue a safety recall.

Levine wrote that “when these Hyundai and Kia vehicles are compared to other similar
vehicles, there is enough of a statistical disparity to suggest a systemic issue that NHTSA must
investigate and seek a repair remedy as soon as possible.”

“More specifically, as of June 7, 2018, a review of all the reported cases to NHTSA of non-collision related fires involving similar class and size vehicles, the Center found 22 reported cases in competitor vehicles as opposed to 120 for the Kia and Hyundai models,” he added.

In January, Hyundai recalled 88,000 Sonatas from the 2006 model year and 2006-2011 Azeras to prevent engine compartment fires. That issue stemmed from an electrical short in the anti-lock braking system’s control module.

A much larger recall of roughly 1.7 million Hyundai and Kia vehicles over engine debris and stalling concerns covered the four models mentioned here. The recall, which snowballed over time, led to an NHTSA investigation earlier this year over the timeliness of the automaker’s response.

In its petition to the NHTSA, the safety group cites fire investigators and one lawsuit that seem to point the finger an an unsecured wiring harness coming into contact with metal, abrading the wires and leading to a short. The NHTSA has 120 days to respond to the petition.