MICHIGAN (NEWSCHANNEL 3) - Truck drivers maneuver several tons of cargo down Michigan highways every minute.

A new study shows that hundreds of thousands of them shouldn't even be behind the wheel.

Right now about 600,000 commercial drivers suffer from conditions like diabetes and narcolepsy. They are conditions that qualify them for full disability benefits, because they can lead to serious issues like heart attacks, seizures and unconscious spells.

Some truck drivers say the reason so many of their peers slip through the cracks is that they find doctors who overlook those medical conditions so they can stay on the road.

"There's a place in Kalamazoo Michigan you go to and they're real thorough. Then there's a place across town and they get you in and out real quick," said one trucker.

Some people say the government needs to bump up their regulations to crack down on these dangerous drivers. Folks in the industry say that would just increase already outrageous trucking costs.

Congress plans to take some kind of action soon. The House Transportation Committee will hold oversight hearings this Thursday.