WOBURN, Mass. (CBS) – The smell of smoke is burned into Lisa Montanaro’s mind. As she drove home to Woburn from Pennsylvania three weeks ago, after her 6-year-old son Nico fell asleep in his booster seat, she started to smell something funny.

“My eyes started to burn,” she recalled in an interview with WBZ-TV in Boston. After a few more minutes, she decided to pull off the highway, check on the car, and fill the gas tank.

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“I don’t know, mother’s intuition,” Lisa explained. “I don’t know, there was just something that was off.”

A faulty seat heater burned a boy from Woburn (Image credit Lisa Montanaro)

She was right — when she went in the backseat to check on Nico and pulled his pillow out from behind him, the car filled with smoke. “I started freaking out,” she explained. “I had gas being pumped into my car at the time. Screaming at my son to get out of the car, get him out, stop pumping the gas.”

The pillow was burned to the seat, and when Lisa ripped it off, it revealed a gaping hole in both the pillow and the car’s rear seat. Nico got a small burn on his hand when she ripped him from the car. His sweatshirt and parts of his blanket had melted together.

Lisa Montanaro hold son’s pillow burned by faulty BMW seat heater (WBZ-TV)

That’s when Lisa learned that before his nap, Nico had turned on the rear seat heater, and it had clearly malfunctioned. “It’s been a great car up until then,” she said. “I mean in a million years we never thought anything like that would happen.”

Auto safety expert Sean Kane of Safety Research and Strategies says seat heater malfunctions are not common, but not unheard of either. “They are not common, but they are certainly known and have been subject to a number of recalls over the years,” he told WBZ. “Typically, they do not result in serious injuries or fatalities, which is the good news. The result of that is often times incidents go unreported especially if the dealer or manufacturer decides to fix the vehicle for someone.”

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Still, Kane says these malfunctions can be dangerous. “The fact is, you are driving a vehicle and you get smoke inside the vehicle,” Kane said. “That can be really problematic and can lead to a crash as well.”

Lisa Montanaro felt that fear once her emotions settled. “If I didn’t pull over and he had woken up on his own, he would’ve gotten up and no matter how he moved he would’ve moved that pillow and he most likely would’ve burned himself and would’ve been screaming,” she said. “I don’t know how panicky I would’ve gotten. It could’ve ended up deadly for all I know.”

A faulty seat heater burned a boy from Woburn (Image credit Lisa Montanaro)

Nico told his parents he’ll never nap in the car again, and Lisa and her husband Tony say they’ll never drive the 2013 BMW X5 again. They’re using a loaner car while the dealership works out the next steps.

“I think for any car that has heating coils, that electrical component,” Tony explained. “If you’re out on a long car ride, you are at risk that car catching fire.”

The Montanaros say they wanted to share their story not to shame the car company, but to spread awareness. “We take a lot of long car rides,” Tony said. “Do I have to worry about my kid being on fire? I don’t want to have to file that lawsuit ever.”

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WBZ reached out to BMW for a comment but did not hear back.