TRINITY BAY, Texas (KTRK) -- During a hot July morning, smoke billowed from a wooden structure surrounding an orphaned oil rig in the middle of Trinity Bay. Dozens of wells that once helped power Texas' oil and gas industry and economy are now decades old and rusting away in Trinity Bay. "My goodness.

I told y'all, 'You never know what we'll find out here,'" Tom Taylor, a recreational boater who grew up on the bay, said. "Sometimes I wish that wasn't true." 13 Investigates joined Taylor on his boat this summer as we observed an oil and gas graveyard of forgotten wells that the state is now responsible for plugging.

Some of the oil wells leaking during our visit are referred to as "zombie wells." About 8,500 wells across Texas are considered orphaned wells, meaning they've been inactive for over a year and have no owner. In some cases, the owners declared bankruptcy, leaving the state responsible for plugging the wells, which can deteriorate and leak combustible gasses into the atmosphere if left unchecked.

13 Investigates partnered with ABC News, which tested 10 abandoned wells in Trinity Bay. Our joint investigation found seven wells leaked combustible gas during our visit. ABC News' team of investigative reporters tested 76 wells across five states and found 40 were leaking oil or combustible gas when we tested them.

"This is just complete failure here. This has got to be probably 50 years old, built strong, but after so many years, it just is dilapidated, and it's pollutin.