The Ford Explorer is the best-selling midsize SUV in the country, with around one million on the road. But hundreds of customers say the vehicles might be making them sick.

Hundreds of people who own Explorers describe it as a sulfur or rotten egg smell coming into the car while they are driving, reports CBS News correspondent Kris Van Cleave. It’s exhaust, from the rear of the vehicle, and they worry it could be toxic. One police officer we spoke with said it nearly killed him.

Dash cam video shows the moment Newport Beach police officer Brian McDowell’s life changed. He was responding to a non-emergency call when he passed out behind the wheel of his 2014 Ford Explorer police cruiser and crashed into a tree.

“I just think, plus or minus one second and I maybe wouldn’t be here on this earth for my kids,” McDowell said.

McDowell has scars from a dislocated shoulder, fractured eye socket and traumatic brain injury, but no memory of the accident.

“I just went out. Just like that,” he said.

Records show McDowell had no drugs or alcohol in his system.

“I just had that nauseous feeling and just feeling like I had a headache,” McDowell said.

But after months of tests, doctors couldn’t find any medical reason why he’d blacked out. Then he learned hundreds of drivers had been complaining about exhaust, which contains carbon monoxide, leaking into the cabin of Ford Explorers, likely through unsealed seams in the rear of the SUV. 

Based on customer complaints and Ford’s own documents, the issue seems to occur while accelerating with the air conditioning active and in circulation mode. McDowell said he believes the car made him sick and led to him passing out.

After monitoring complaints on the issue for two years, the National Highway Traffic Safety Administration (NHTSA) finally launched an investigation in July, citing 154 customer complaints about exhaust in Ford Explorers model years 2011 through 2015.

But CBS News discovered that’s grown to more than 450 complaints, some involving 2016 and 2017 models, which are not part of NHTSA’s investigation. While declining to comment further, NHTSA maintains there haven’t been any serious injuries — something McDowell’s attorney, Brian Chase, disputes.

“When I saw that they said there were no injuries, we immediately got NHTSA on the phone,” Chase said. “I gave them all the information we had in the lawsuit.”

Retired Army vet Ron Booth took us for a ride in his 2015 Explorer that’s been in for repairs on this issue five times, most recently in November. He said he worries about what he’s breathing in “a lot.”

A few minutes into the drive: “Now you can smell it. You can definitely smell the exhaust smell right now, and we get that all the time,” Booth said.

Ford’s known about the issue since at least 2012, when the company issued its first of three repair bulletins to dealers aimed at fixing the problem.

“Ford has tried to fix it and they can’t,” Booth said.

In a 2015 deposition, a company representative acknowledged it appears to be a “design issue.” That remains unresolved – or as he said, “we’re working on it.”

The automaker has stopped short of notifying customers, but told CBS News: “In rare circumstances, there have been instances where customers detected an exhaust odor in Explorers,” adding the issue “poses no safety risk.”

Booth can’t afford a new car so he’s driving on with a carbon monoxide detector. Newport Beach police also told us they had implemented new “safety measures” in the vehicles after McDowell’s accident.

“Just as a precaution, carbon monoxide detectors have been installed in all the patrol vehicles… some of those detectors had gone off,” McDowell said.

McDowell has filed a lawsuit against Ford over his injuries. His isn’t the only exhaust-related case. In August, Ford agreed to settle a class action lawsuit filed in Florida. The amount of the settlement is unknown and won’t be finalized until May. Another class action filed in New Jersey is still pending. Ford has denied all the allegations in that case.

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