Since Marion Smith began caving in 1966, he's squeezed into innumerable tight spaces like the one he entered Friday afternoon.

But this particular cranny he wedged himself into while looking for new cave openings in Van Buren County, Tenn., was more akin to an impassible hole.

A rock on Smith's left fell and pinned him in to the space, resulting in a rescue effort that included nearly 50 people and a trip to the hospital that Smith, 71, cut short after deciding he was ready to leave.

Crews had to micro-blast the rock to dislodge it.

"I just yielded to the old temptation that I've yielded to for many decades and foolishly went in," Smith said of the maneuver that resulted in his trapping. "And as soon as I got in the thing, I literally said, 'I'll never get out of here.' I literally said that."

Though Chattanooga-Hamilton County Rescue Service assistant chief Buddy Lane, a longtime friend of Smith, said that the immediate decompression of escaping such a situation can be dangerous and even deadly without proper medical attention, Smith is hoping to return to the caves today.

"This incident, all it did was screw up my plans for the weekend," said Smith, who pays no mind to the inevitable physical limitations of age.

When Sports Illustrated came to Van Buren County in 2003 to feature Smith and the environmental battle he participated in to prevent a Van Buren County cave from becoming the destination of a sewage dump, the magazine portrayed Smith as a successful but aging spelunker.

Marion Smith, 71, has been caving since 1966. Despite an incident that sent him to the hospital Friday, he plans to resume caving immediately.

"Despite a bad back, fading eyesight and other infirmities of age, he is impervious to pain, unable to sit still with passage ahead of him," writer Michael Taylor said of Smith, then 60 years old.

Those words remain true of Smith. In fact, he has only sped up. Though quick to clarify that other cavers are taking on the most challenging passages, he said he spent more time underground in 2013 than any other year in his life.

"He's so hardcore, you wouldn't believe it," Lane said.

Smith was part of a small group that in 1998 discovered the Rumble Room. Now known as one of the largest cave chambers in the United States, the Rumble Room remained a secret known only by Smith and the other discoverers until the sewage proposal threatened the cave and its underground stream system in 2000. The proposal brought national media attention, including the Sports Illustrated piece.

Paparazzi no longer tag along with Smith on his expeditions, but Smith does not do what he does for the attention or even just the thrill of discovering untraveled underground spaces.

Much of his interest in caving is derived from the historical context that the area caverns hold with their ties to the Civil War when they were mined for saltpeter.

Smith relocated to Van Buren County because of its caving allure after retiring from the University of Tennessee, where he researched and edited on President Andrew Johnson.

"It is my passion, my all, frankly, even though I do have other interests," said Smith, who considers himself a caving "lifer."

"Even if I'm physically impossible to go in a wild cave, surely I can be put in a wheelchair and wheeled to a commercial cave," he said. "And if I can't be sitting up in a cave, surely they can put me on a stretcher and wheel me into one."

Contact David Cobb at dcobb@timesfreepress.com or 423-757-6731.