Pretty sure that stuff is supposed to stay outside the cabin.
The National Highway Traffic Safety Administration (NHTSA) is taking a look at the Ford Explorer over concerns about exhaust gas leaking into the cabin. The investigation was launched after 154 complaints were submitted about a powerful exhaust odor infiltrating the interior. The Explorers being looked at are MY 2011-2015. The NHTSA has not revealed how many SUVs might be caught up in the probe but it has linked one crash to the issue. Fortunately no one was injured in that incident.
According to owners the issue is most noticeable under full acceleration, when climbing up steep hills or when the A/C is on and set to recirculate. While those three scenarios don't cover all driving exhaust gas seeping into the cabin isn't something to take lightly. Ford is said to be fully cooperating with the investigation and has issued two technical service bulletins. But owners say that these fixes don't change anything. For now the issue is in its infancy and as such we'll wait for more information to come out before weighing in. What we can say is that a recall could involve a lot of cars. In 2015 alone Ford sold 249,251 Explorers. And the PR hit from a recall like this would be bad. Cars filling themselves with poison gas doesn't read well any way you write it.