When Carol Nash heard screams for help, she rushed out of her apartment in her nightgown and found her SUV burning in the parking lot — but couldn't get close enough to save her son, sitting in the driver's seat.

"I could not do anything except stand there and watch him die," Nash told Go Public.

Keith Nash, 48, burned to death on April 19, 2017, in his mother's 2014 Kia Soul while the vehicle was parked outside her low-rise apartment building in Cincinnati, Ohio.

His mother says Kia has never contacted her to explain what happened.

She was devastated when she learned the company issued a recall for the SUV for a potential fire risk in February — two years after her son died.

"I suffer on a daily basis with this because I have no answers," she said.

Keith Nash, left, died in a car fire in 2017. Investigators weren't able to determine the exact cause of the fire, but Keith's mother, Carol, wants answers from Kia. (The Nash family)

Since 2015, Korean carmakers Hyundai and Kia have recalled more than three million vehicles in North America over concerns the engines could fail at high speeds or burst into flames.

A Go Public investigation revealed other models weren't on any Canadian recall lists when drivers experienced catastrophic engine failure or fires. After the CBC News investigation, both Kia and Hyundai vastly expanded the number of recalls in Canada. Hyundai is a part-owner of Kia.

Been wronged? Contact Rosa and the Go Public team

Automobile safety advocates and vehicle owners accuse the two companies of downplaying fire and engine failure reports and taking too long to roll out recalls, raising questions about when they first knew of the safety issues and whether more vehicles might still pose a risk.

"We now have multiple years of reports of these catastrophic engine failures and the very slow reaction from the companies," said Jason Levine, executive director of the Center for Auto Safety, a consumer advocacy group based in Washington, D.C.

The automakers say they are on top of the problems and are working with Transport Canada to address them.

Kia says fire not related to recall

The official cause of death for Keith Nash was smoke and gas inhalation. Fire investigators believe the blaze started in the engine area, but weren't able to determine the exact cause.

In an email to Go Public, Kia suggests that fentanyl and heroin found in Nash's system may have rendered him unconscious and unable to get out of the burning car. The auto giant also says Nash may have caused the fire by simultaneously pressing down on the accelerator and brake pedals while the vehicle was in "drive" mode, causing the transmission fluid to ignite — an issue unrelated to the recall issued two years later, the company says.

Kia says the fact Nash was intoxicated may explain why he was unable to get out of the burning car. (Sharonville Police Department)

Go Public put that to Hamilton mechanic Chris Solodko, who has repaired dozens of Kia and Hyundai vehicles following engine failures. He says it's very rare for transmission fluid to catch fire.

According to Solodko, Nash would have had to apply an enormous amount of pressure to the brake while holding the accelerator down to keep the SUV from moving and causing the transmission fluid to heat up to the point of catching fire.

No car 'should blow up and burn like that'

Carol Nash isn't the only one who wants answers.

Go Public has heard from dozens of Hyundai and Kia owners who say they've experienced catastrophic engine failure or fires with vehicles that aren't part of any recall.

Robert Mitchell recalled getting a panicked phone call from his 30-year-old son Ryan on Aug. 11.

Ryan told him he was driving the family's 2016 Hyundai Elantra down one of the busiest highways in the Toronto area — the 403 — when the engine seized and started to smoke before bursting into flames.

The Mitchells' 2016 Hyundai Elantra caught fire while Ryan, right, was driving on a busy highway near Toronto. (Yanjun Li/CBC)

"I don't think that a car — any car — should blow up and burn like that," Robert Mitchell said from the family's home in Mississauga, Ont.

Mitchell's insurance company paid for the destroyed car. According to Transport Canada, the fire started in the engine compartment, but the cause is unknown.

A 2018 Hyundai Elantra that caught fire in March in Windsor, N.S., ended up igniting the duplex that it was parked in front of. (Paul Palmeter/CBC)

Another Hyundai Elantra, a 2018 model, is at the centre of a fire investigation in Windsor, N.S.

On March 27, an Elantra that had been parked in front of a duplex for hours burst into flames. The fire spread to the building, but the families inside escaped unhurt.

Video of overnight fire that destroyed century old home in Windsor but two families escape via dramatic rescue.<a href="https://twitter.com/CBCNS?ref_src=twsrc%5Etfw">@CBCNS</a> <a href="https://t.co/0Rj84mGTtv">pic.twitter.com/0Rj84mGTtv</a> —@PaulRPalmeter

Hyundai Canada and Transport Canada didn't confirm the cause of the fire. Transport Canada says the investigation is now in the hands of a private insurance company.

Bigger than one type of engine

Kia and Hyundai are now facing a flood of lawsuits in the U.S. and at least two in Canada over the engine breakdowns and fires.

The recalls issued so far cover certain Hyundai and Kia models produced after 2011, mostly involving a variety of safety concerns around what are called Theta-II engines. In some cases, the recalls address mechanical issues that could lead to engine failure. In others, software is installed that gives drivers advance warning of an engine problem.

Levine says his organization is seeing other types of engines breaking down or burning. He points out, for example, that Nash's Kia Soul — which was recalled in February — and the Hyundai Elantra don't have Theta engines.

"It's certainly troubling that it's going on at least several years ... these non-crash fires across a variety of makes and models, not only the Theta-II," he said.

Companies respond

Go Public asked both Kia Canada and Hyundai Canada when they first knew about the engine defects, but neither company answered the question.

Hyundai Canada was asked if it had a fix for the engine problems, but again, it didn't respond to the question directly.

In an email, Hyundai Canada told Go Public that over the past 10 years, there have been 12 cases of engine fires determined to be a result of an issue with the vehicle itself.

"We stand behind the quality of our products and continuously work to ensure the highest safety standards for our customers," spokesperson Bianca Pettinaro wrote. She says the company has issued notices for all the vehicles that could be affected and is keeping an eye on the issues.

Hyundai and Kia have recalled more than half a million vehicles in Canada since 2015 due to potential risk of engine failure or fire. (Associated Press)

In another email, Kia Canada spokesperson Mark James wrote, "A vehicle engine failure or fire can occur due to any number of complex factors, including inadequate maintenance, arson, or some other non-vehicle source, all cases must be carefully evaluated by trained technicians to determine its cause."

He says Kia has a strong safety record and promptly reports safety-related defects to Transport Canada.

Automakers under investigation

Hyundai and Kia are now being investigated by regulators in several countries — including Canada and the U.S. — over safety defects that may have led to engine failures and fires not caused by crashes.

Nearly 540,000 Hyundai and Kia vehicles are now under recall in Canada due to risk of engine failure or fire. Transport Canada is investigating whether more models should be part of the recalls after getting approximately 200 complaints about engines since 2014.

The National Highway Traffic Safety Administration (NHTSA) in the U.S. is investigating engine failures and fires in certain model years. As of the end of March, the regulator had received more than 3,000 complaints of fires not related to collisions, including 103 injuries and one death.

Those are the kind of answers Carol Nash is looking for — and that need to come from the automakers involved, she says.

"I just don't want this ever for any other parent or any other mother to go through what I went through on that day."

Last November, both Kia and Hyundai refused to testify at a congressional hearing that was scheduled to look into the engine fires. That hearing was cancelled after the automakers declined to attend.

Certain vehicles among the models listed above have been recalled in Canada since 2015. In total, more than half a million vehicles are affected by the recalls.