NASHVILLE, Tenn. -- The Channel 4 I-team is hearing stories about trash trucks that haul garbage at high speeds on the highway. According to former employees, these trucks are often overweight and overworked to the point of being a danger on the roads.

Video: Garbage Hauler Criticized For Safety Procedures

Mr. Bults Inc. is the nation’s biggest garbage hauler and under contract to transport tons of Nashville trash to the Middlepoint landfill in Murfreesboro.

"MBI is pretty much the only game in town hauling that stuff to the landfill, but for a few dollars it's not worth somebody's life," said former MBI truck driver Todd Turner.

After the Channel 4 I-Team uncovered the secret state program for dumping low-level radioactive waste, Channel 4 News started hearing from truckers. They weren't so much worried about what they were hauling, as what they were driving.

"The safety record for these trucks is outrageous. Going down the road, I’ve had tires fall off. I know of another driver who was going up the hill, and his trailer fell off the truck. They run the death out of these things, and they don't maintain them very well at all,” said a former MBI trucker who did not want to be identified for the story.

MBI truckers are paid by the ton and the run. Get a lot of garbage dumped, and do it quickly. But an overloaded truck is much harder to stop.

Turner has a stellar driving record and quit MBI after just 10 days on the job with the company.

"The tractors were in such disrepair. The jaws on the fifth wheels that hold the trailer on the truck were so worn out that some drivers were actually losing trailers in the yard. I got to the point where I didn't want to run illegally,” said Turner.

He has the paperwork that appears to support his claim. Channel 4 News showed the paperwork to the Tennessee Highway Patrol.

"These wouldn't surprise me a bit if some of these were in excess of 100,000 pounds, when you take the weight of the garbage and the trash and then you combine that with the weight of the vehicle with the track of the trailer,” said Cpt. Steve Binkley of the Tennessee Highway Patrol.

"I've carried up to 115,000 (pounds), and that happens on a daily basis. Nobody ever goes out of there at 80,000 pounds, never,” said the trucker, who did not want to be identified.

And since there's no weigh station on the way to the dump, it can be a free ride.

“If they were crossing a regular-scale house with that kind of weight on it, there would be huge fines involved," said Turner.

“If they get stopped, they don't really don't care anyway. Because if they get stopped, the company just pays the fine. They're a nationwide company, so they've got millions of millions of dollars, so really they don't care,” said the trucker, who did not want to be identified.

But there are some numbers about which the companies are bound to worry. MBI's score on a national safety database is 94 out of 100.

That number sounds good, but the trucking game is like a golf game -- the lower the score, the better.

“What if I told you they had a 94?" asked reporter Demetria Kalodimos.

"Out of 100? That crazy. That's atrocious for something as simple as repairing a truck. To take the lives of the public and the drivers so carelessly, that just to me is appalling,” said Turner.

That same database shows that of the nearly 200 interstate trucking firms in Tennessee, 10 percent, just 27 firms, have a worse score than MBI.

MBI has had 92 crashes, five of which involved deaths, in the last two years. Its vehicle score of 67 isn't very impressive, either.

“It would put them in the bottom 33 percent as far as the vehicles being kept safe,” said Binkley.

The THP now said it's seen enough and has promised to take a closer look at MBI.

“We need to set up something roadside to focus on these vehicles that are using this routes that may be going to the landfill,” said Binkley.

Channel 4 requested an interview with MBI, and the company declined. But it did send a statement saying the following:

“Mr. Bults Incorporated has been a responsible member of the Greater Nashville Business community and has nothing to hide with regards to our maintenance and safety practices. In fact we participated in a Federal Department of Safety Audit in December 2006 and were found to be in compliance in all areas."

Channel 4 has filed a Freedom of Information request to obtain a copy of that safety audit to take a better look at the companies’ scores.