Cavers' biggest problems include loose rocks, the lack of preparation and the risk of slipping.
Hanson and others involved in the Tristate Grotto spent much of Saturday in a cave in West Virginia, cleaning up graffiti. They have been tackling clean-up work at problem caves since January.
The National Speleological Society, with 12,000 members nationwide, is dedicated to advancing cave sciences, cave conservation and the education of cave explorers.
Hanson advises cavers take care before they begin their underground adventure. Proper clothing is important, starting with shoes, he said.
"You need shoes with good traction, ankle support, and preferably drain holes, because some caves have a lot of water," he said. Sneakers and tennis shoes can prove slippery, he said.
"A helmet with a good chin strap and a light mounted on top is absolutely necessary," said Hanson, 48. "Flashlights can be pretty unreliable, and you need the hands free for all kinds of other reasons."
He said all cavers should carry at least two sources of light, one of which should also be a source of heat.
Hanson also advises cavers to pay attention to where they're going.
The cave does not look the same going in as it does going out, he said.
"Don't forget to look behind you periodically as you walk through the cave," he said. "It can fool you."
And if you get lost, it's best not to wander around, he said. "You're using your energy and using the light source if you wander. And no one person should wander away from a group. Stay together."
"A lot of it is common sense, knowing what to do and doing it," he said.
He also warns against acting macho or gung-ho when you're inside a cave.
"They are usually the ones that get hurt," he said.
The Tri-State Grotto meets the second Wednesday of every month.
For more information call (1-301)432-4182.