A major development resulting from an ongoing CBS News investigation could affect more than one million Ford Explorer owners.
The National Highway Traffic Safety Administration says the number of complaints and injuries related to possible carbon monoxide leaks is much higher than previously thought.
Thousands of complaints have now been filed with NHTSA and Ford about possible carbon monoxide leaks in Ford Explorers, prompting NHTSA to expand its probe to include 2016 and 2017 models.
A 2016 Henderson, Louisiana police Explorer was badly damaged in a crash after officers say its driver passed out from carbon monoxide exposure in April.
"When she was treated at the hospital, we had requested testing for carbon monoxide and her levels came out near lethal," said Henderson Police Department Captain James Thibodeaux.
On Thursday, that officer filed suit against Ford and many more owners of Explorers model years 2011 through 2017 are reporting carbon monoxide appears to be seeping into their vehicles.
NHTSA now says more than 2,700 complaints have been lodged against the automaker and 41 people have reported injuries.
Sergeant Zachary LaHood's dashcam was rolling as he called for help. LaHood was the first of 18 Austin, Texas police officers to be treated for carbon monoxide exposure.
The city has removed 67 of its Explorers from service after they set off carbon monoxide detectors. The police union says all 439 need to be off the streets now.
"If this is not done by the end of the week, we're going to have big problems and my officers are worried about it," said Ken Casady, head of the Austin Police Association.
In 2016, 48 percent of law enforcement vehicles were Ford Explorers. Departments across the country have added carbon monoxide detectors.
The bulk of the complaints come from regular Ford owners – like Stacie Jones.
She traded her 2014 Ford Explorer in for a 2017, but says the problem didn't go away.
"It's frustrating because at this point, I don't know what I am going to do," Jones said.
NHTSA contends it doesn't have any proof the injuries reported were caused by carbon monoxide, though investigators say levels of that gas may be elevated during certain driving scenarios.
In a statement to CBS News, Ford said, "Safety is our top priority. A dedicated Ford team is working with police customers, police equipment installers, Police Advisory Board members and NHTSA to investigate reported issues and solve them. Customers with concerns about Explorers and Police Interceptor Utilities can call our dedicated hotline at 888-260-5575 or visit their local Ford dealership."