Caves and blue springs dot the cactus-covered plains of east-central Mexico. Here the rivers flow underground, gathering heat and minerals, gouging tunnels under the desert. Above the teeming aquifer, a flat, rocky scrub stretches from the El Abra Mountains to the Gulf of Mexico, 30 miles to the east. Home to snakes, scorpions and a few scraggly cows, the plain is baked by the sun and blasted by "el viento del norte," a hot northern wind that comes often. When it comes, it lingers for days.
April 6, 1994
At high noon the wind rages. I stand with a handful of reporters and ranchers above an enormous water-filled sinkhole called Zacatón. We stare down 70 feet at the warm thermal spring. White plumes of sulfur swirl through the water like milk. We walk the perimeter of the hole, straining for a glimpse of two men who should soon rise from setting a world scuba depth record, achieved in absolute darkness 1,000 feet below the water's surface.
The hot wind snatches hats from our heads and words from our mouths. Bright circles of floating saw grass, 10 to 30 feet in diameter, bounce across the water like slow-motion billiard balls. I try to comprehend the spring's impossible depth. If the Empire State Building sank to the bottom, I could step onto its main observation deck from where I stand.
Somewhere down in the water is Sheck Exley, a high school calculus teacher and karate expert from Live Oak, Fla. Exley, 45, is also the undisputed master of deep scuba, which is practiced mostly in cave pools. He has logged more than 3,000 successful cave dives, far more than anyone else. It is Axley's own depth record of 867 feet, set in another Mexican spring in 1989, that he and a colleague, Jim Bowden, set out to break this morning.
Bowden is a 52-year-old adventurer and dive instructor from Austin, Texas. Five years ago he discovered Zacatón after more than a decade spent searching the springs and caves of Mexico and Central America for places where no human had been. Under Exley's tutelage, Bowden trained for the past year for this dive. He poured thousands of dollars into the equipment needed to make a record descent. He recovered from a case of the bends—suffered on a training dive at Zacatón in November—that would have retired, if not killed, other cave divers.
Closer to the surface, yet hidden from us by the suspended sulfur, three support divers hover, waiting to assist Exley and Bowden in an anticipated 10-hour decompression. A 1,000-foot descent packs nitrogen into a diver's blood like bubbles in beer; rising too fast would rip his joints and muscles. The hours of slow ascent, while they breathe exact mixtures of oxygen, helium and nitrogen at prescribed levels, will let the divers properly outgas, or shed, the excess nitrogen.
Parallel ropes, 25 feet apart, are tied to rocks at the water's edge. They dangle halfway down the flooded pit, holding in their places more than two dozen dive tanks from which Bowden and Exley will breathe on their way back to air. Two hours ago the explorers had entered the sinkhole by swimming through a 600-foot-long cave, thus avoiding a difficult rappel down the cliff face. Hidden 30 feet below the floating grass, this natural tunnel carries currents that rise from the depths of Zacatón and spill out from a nearby spring.
When at last two of the support divers surface, the wind gusts so that none of us above can hear what they say. But we can see. We can see a woman in a wet suit grabbing the shoulders of another woman, holding her, placating her. We can see bubbles, as regular as breath, plopping up near one of the ropes. We can see the other rope hanging in water that is chillingly still.
The sun beats down. The hot wind blows. The third support diver surfaces to join the other two. Beside them, bubbles rise from one line only.
Two photographers use their telephoto lenses to close in on the women in the water. What they see makes them stop snapping frames. "Oh, my," one of them says. He lowers his camera and passes it to me.
I bring into sharp focus the tearstreaked face of Mary Ellen Eckoff, who once held the women's world scuba depth record and is the longtime companion of Sheck Exley. Just then she looks up and screams, "No!"
The shout echoes from the limestone cliff walls and dies in a sob that the wind carries to us all.
In 1993 more than 6,000 people were certified as cave divers by the National Speleological Society Cave Diving Section, in Branford, Fla. According to Joe Odom, chairman of the society, there are now more than 14,000 certified cave divers, compared with just a thousand in 1984. Yet from rank novices to experienced explorers, all cave divers are continually faced with their own mortality.
Cave diving is to open-water scuba as flying an F-16 is to piloting a Cessna. The difference is that the weekend pilot can't get at the stick of a fighter, while Joe Scuba needs only to find an underwater hole and swim in. In this sport nearly all errors are fatal. Most cave divers with more than five years' experience have participated in at least one body recovery. Sheck Exley made 36 recoveries.
The dead are usually open-water divers, sometimes even dive instructors, who were unaware of the special hazards of submerged caves: loose ceilings; vertigo induced by huge irregular chambers; mind-numbing cold and depth; flashlights that won't operate below shallow depths; silt that rises from the floor of disturbed passages to darken water that was transparent going in. Bodies have been found within 10 feet of a silt-obscured entrance, fingers scraped raw from a last, desperate attempt to claw through solid rock.
Sometimes untrained cave divers panic and drown for no discernible reason. At least four died in the past decade with more than 30 minutes of air left in their tanks and an easy way out.
Those who make it through proper cave training and certification enjoy a safety record far better than that of open-water divers. Basic Cave Diving: A Blueprint for Survival is one of the first manuals read by prospective cave divers. To bring home the danger of the sport, each chapter begins with an account of an accident, illustrating how the flouting of a particular safety procedure cost a life (or several). Such reading can make even the laziest student suddenly attentive.
The author of this and six other cave-diving texts, and hundreds of published cave-diving articles, is Sheck Exley.
June 29, 1968
Saturday. Wakulla Springs, Fla. Children laugh on the beach. Teenagers jackknife and cannonball from the high dive. The 72° water hums with the pinging motor of a glass-bottomed boat. Tourists pass over the powerful boil, gawking at the great cave 120 feet below. The water carries another sound, something distant, rhythmic: Hiss. Bubble. Hiss. Bubble.
Pure water flows under the whole of north Florida, carving up the hard white limestone and chuckling forth at hundreds of great blue springs, of which Wakulla is the greatest. Today, once again, its deep water has lured the Exley boys, 19-year-old Sheck and 16-year-old Edward, all the way from Jacksonville.
Irby Sheck Exley Jr., home from the University of Georgia, dives every weekend, paying for equipment and compressed air with a summer job in the parts department of his father's Volkswagen dealership. In the five years since he took a basic scuba certification course at a YMCA pool, he has gained a reputation at the Panhandle's dive shops. It's said Shock can make a tank of air last longer than it ought to, can keep a calm head at depths that should knock him woozy with nitrogen. Maybe it's the mental discipline of karate—he's only months away from a black belt—that lets film slow his heart and lungs by sheer will, allows him to think straight at 300 feet below. Maybe it's his obsession with gear, the way he rebuilds half the things he buys, finds and corrects potential flaws in scuba regulators designed by Navy engineers.
Sheck might go all afternoon without saying two words. His younger brother, on the other hand, has the gift of gab. There's an easy and almost infectious wildness about Edward. Back when 10-year-old Sheck was cataloging—by sex, size and species—the snakes that lived in the swamp across the street from their suburban home, seven-year-old Edward was slipping them down girls' dresses.
Signs in the Wakulla parking lot prohibit scuba. But Wakulla is a great place for free diving, for the brothers to see how long they can hold their breath and how far they can push the needle on Sheck's new depth gauge. They swim out to the deep water, where they take turns strapping the stainless-steel dial on their wrists.
Over and over again they hyperventilate and head for the bottom, waiting until the last possible second to turn and point their bursting lungs toward the Honda sun. Edward pushes the needle to 30 feet. Sheck takes it to 35. Edward makes 42. Sheck focuses his mind, relaxes and hits 50 feet. Edward laughs and sucks in mighty gusts, hyperventilating to the edge of unconsciousness before plunging down. Sheck watches his brother pass 50 feet and keep going, swimming deeper than either of them has gone without scuba. He watches Edward start to turn and suddenly go limp. He watches Edward begin to float slowly downward.
Sheck dives back down to rescue Edward, but without scuba it's impossible. He climbs out of the water, shouting for help. He runs to his car, where he has an air tank, but he's too exhausted to attempt another dive. Another swimmer straps on the gear and runs back down the beach as seconds tick by. He enters the water and pumps his fins. Bubble. Hiss. Bubble. Hiss. The swimmer pulls Edward from the sandy bottom and up to the beach. Sheck pounds the water from his brother's lungs before a panicked crowd, willing Edward to live, calmly and correctly breathing life into him. Just life enough to get Edward into an ambulance and onto a machine. Late that night the machine is turned off. Edward is gone.
After Edward's death, Sheck turns his grief into a drive for perfection underwater, for safety and technique, for achievement without mishap. He begins diving with Ned DeLoach, the most experienced diver of that time. By 1970 Exley holds world records for both linear distance traveled and depth achieved in a cave dive. His gear designs and safety procedures are adopted by much older, more experienced divers.
People pay attention to Exley, pay him compliments. He always turns the compliments around, praising the speaker: I'm sure you could have done the same. Probably a lot better. The important thing is that we had a safe dive. He confides to a friend, "I can't stop diving, but I can make it safer. I've got to. I can't put my parents through that kind of pain again."
Exley makes his black belt, spends hours a day in exercise. He writes, reads poetry, plays the piano, toys with differential equations. He gets his business degree, returns to Jacksonville and joins his dad's car dealership. By the end of the decade he is the firm's general manager.
April 21, 1980
As a 20-year-old senior at Florida State University, I have begun to climb and crawl into the air-filled caverns dotting the Florida Panhandle, crystal-lined tunnels scoured by the springs of a previous geologic age. I have joined a university cave club, progressing to the complex passages of Climax Cave, an eight-mile labyrinth in south Georgia.
The muddy rooms of Climax are punctuated with sumps, or cave pools, some of them leading to known tunnels flooded in the 1950s, when construction of a dam 30 miles away raised the area's water table. Our club suspects that other sumps lead to virgin territory. This weekend five cave divers and 50 cave sherpas—volunteer labor to hump tanks and gear—have gathered at Climax for a major underwater push. One of my roommates and I are sherpas. The support teams work 10-hour shifts, hauling gear to and from three distant in-cave sites, unlikely blue holes opening amid the muck and limestone.
My job is to lower heavy air tanks down a 30-foot entrance pit and then ferry them, one at a time, through a twisted 300-foot crawlway, a sandy tube punctuated by tight squeezes. Other sherpas move tanks from the end of the crawls to the widely separated pools. We work well in advance of the divers, who are to arrive "fresh" for the penetration effort.
The divers have varied backgrounds. There's a clean-cut aerospace engineer and a long-haired, tie-dyed Southerner whose main source of income is selling his own plasma. Yet they all seem pretty much alike. Each is quietly determined, detail-oriented, picky. After the divers trickle in, I watch two of them unpack (each carries about four large duffels) and gear up for a sump. It is impossible to observe such a highly regimented routine without thinking of a preflight check.
One of the quietest in the group is Exley. Of medium height, powerfully built, he looks as if he stepped from a turn of the century boxing poster: thick mustache balanced on a sharp face; short, wavy brown hair; muscular chest and arms; skin as pale as a shark's belly.
Exley asks my roommate to lead him to his sump, in the room called Batman's Den. There's no questioning the quiet authority in his voice. They push on.
Later I learn that my friend took Exley down a wrong fork. They spent four hours lost, eventually finding their way from the maze of passages to Batman's Den. Exley, fatigued from the difficult caving, decided to call off his dive, saying that a primary safety rule is never to dive when tired.
The other two teams dive without incident but also without major discovery.
The haul out proves as long and difficult as the haul in. As I shove an unused air tank back through the crawls, a protective valve cover malfunctions. Nudged by the tunnel wall, the valve twists open, spewing air and sand in my face. The sudden wind extinguishes my carbide miner's lamp and shoots sand down my coveralls. I can't reach the valve, so I lie in darkness for the few minutes it takes the tank to empty, my eyes shut tight against the grit.
I imagine myself as a diver, the crawlway as a water-filled sump and this tank as my last. I picture the escaping air pooling into bubbles in the ceiling. In water, the sand I lie in would become a brown, enveloping fog. I would float upside down, my face pressed to the roof, and breathe for the five or ten minutes it would take the loose air to vanish into tiny channels in the rock. If I were very near dry cave, I would hyperventilate, then swim for it. If not, I would have time to compose a few last words for my dive log.
The tank expires with a hiss. I light my lamp and resume the schlepp out of Climax, resolving never, under any circumstances, to go cave diving.
Diving for depth increases underwater danger geometrically. The tremendous pressure reduces body volume by up to a third, leaving divers swimming inside suddenly huge wet suits. Descent on compressed air can cause nitrogen narcosis (also called rapture of the deep), a dangerous light-headedness that can lead to fatal errors of judgment. Simple tasks become confusing; divers may feel something similar to a drug-induced euphoria. Meanwhile, oxygen becomes increasingly toxic. Dive tanks empty quickly.
At extreme depths some of the gases that divers must breathe—usually helium and nitrogen—themselves become toxic. As divers push below 600 feet, they are exposed to perhaps the greatest danger of all: high-pressure nervous syndrome (HPNS), a neurological reaction to rapidly increasing pressure. The eyes shrink, causing divers to see flashing auras around people and objects. HPNS can cause violent body tremors, convulsions, hallucinations and death.
Cave divers face the near certainty of HPNS on deep descents. The syndrome often hits in combination with a condition called compression arthralgia, known to Navy divers as "no joint juice" because it feels as if their knees, elbows and wrists have suddenly rusted solid.
In the mid-1980s Exley becomes intrigued with research on scuba and rapid decompression. He studies the records of pioneering mixed-gas dives in submersible habitats that went as deep as 991 feet. He locates a number of very deep water-filled caves in Mexico and decides that rapid descent on mixed gases is the only way for him to see where the caves go. He begins diving with Jochen Hansenmayer, a German who took away Exley's early depth record in the '70s and later set an open-circuit (as opposed to submersible-habitat) scuba mark of 656 feet.
The deep work involves travel to France, Mexico, the Caribbean and elsewhere. In 1984, Exley quits the car dealership and begins teaching advanced algebra and calculus at rural Suwannee High School in Live Oak, Fla. On weekends and school holidays and in the summer he is free to travel to deep sites.
The years Exley spent training advanced divers have helped him develop a passion for teaching. He becomes popular at the high school. He puts his home number on the board and says, "Call me day or night if this stuff gives you trouble." Soon students are calling with troubles that have nothing to do with differential equations. Exley makes personal projects of wild 16-year-old boys who have had brushes with the law or are on the verge of dropping out. One by one, he pulls them into the karate club he establishes. He teaches them to avoid danger by physical and mental discipline, to take control of their lives by thinking. One by one, he calmly breathes life into them.
In January 1989, Exley establishes a record for the longest distance traveled in a single cave dive, 10,450 feet. By the time he comes up, he has been submerged for 14 hours, a third of that in decompression—itself a world duration record. That March, in a Mexican cave called Nacimiento Mante, he sets a new open-circuit depth record with a dive to 867 feet.
Unlike other cave divers at the highest levels of achievement—notably Bill Stone and Wes Skiles—Exley makes these record dives without fanfare. He doesn't seek support from the National Geographic Society or the BBC. After he breaks the depth record, Good Morning America calls to invite him on the show. So docs Today. Exley turns them down.
One cave diver who stops by Exley's camp at Nacimiento Mante is Jim Bow-den. Like Exley, Bowden labored for years in a family business—an Austin photo studio—and then gave it up for what he calls "the old Star Trek syndrome": going where no man has gone before. Traveling through Mexico and Belize on a shoestring, he has discovered and explored more underwater passages than many huge, well-funded expeditions.
Bowden and Exley hit it off. Both love exploration for its own sake. Both are dive instructors who seek to instill confidence and a dedication to safety in their students. Both have studied literature and love to quote romantic poetry. And both know the secret locations of some very deep holes that no divers have entered. Sitting in Exley's camp, they decide to teach a cave-diving class together and to develop plans for very deep dives.
Feb. 22, 1990
The Florida sunset spreads out in pastel bands, orange sherbet reaching into pale turquoise. Two metal sheds sit beside Exley's modular home; in front of one shed is a Ford cargo van with Mexican tourist stickers on the windshield. Exley is loading tanks into the back of the van. He greets me and says, "I thought maybe we could meet M.E. for dinner."
M.E. is Mary Ellen Eckoff, the world's most experienced woman cave diver. A tanned, good-looking woman with a Southern accent, Eckoff is a grant-writer for Florida school boards and has trained more than a hundred cave divers, logging more than a thousand dives in the process. In 1987, at Nacimiento Mante, she set a women's depth record of 400 feet.
Eckoff and Exley met in 1977 and were married in 1983. The marriage lasted only three years, but the diving relationship and love somehow endured.
Exley and I climb into the van and head down winding blacktop through scrub pine. On the console are a couple of swollen, water-warped paperbacks, cheap science fiction, with the pages glued together. These Exley uses to pass the time during long decompressions. He can't finish a novel on the surface, after it dries, but next time down, the pages will become pliable once more.
"Why do such deep dives?" I ask him.
"I held both the world depth and distance records in 1970," Exley says. "I thought it would be nice to hold them both again before I retire. It just took me nearly 20 years to do it." He pauses before adding, "I wanted to get to a thousand feet. It's a nice round number. But that might be pushing it. I'm going to have to hang up my tanks—at least from that sort of thing—pretty soon. I guess the real reason I'm doing it is I just want to know what's down there."
We meet Eckoff at a Live Oak barbecue house. As she and Exley share diving tales over heaping plates of ribs, both show playful sides I've missed from watching divers only in caves. Eckoff describes the pranks Exley and his regular dive partner, Paul DeLoach (no relation to Ned), have pulled on each other during decompressions. There was, for instance, that time at Cathedral Canyon, the cave in Exley's backyard near Live Oak.
The cave begins as a flooded pit, 130 feet deep. Twenty feet below the surface, a small ledge cluttered with rotting logs, concrete blocks and other debris makes a convenient decompression stop after deep dives. Once, as DeLoach sat on a log, dozing through the wait, Exley tapped him on the shoulder.
DeLoach looked up to see his partner standing at the edge, a cinderblock in his hands. Exley shook the block a couple of times. DeLoach shrugged. Exley grinned around his mouthpiece, then tossed the hunk of concrete over the cliff.
Only then did DeLoach notice that the cinderblock was tied to a coil of nylon line. Rapidly uncoiling nylon line. While he napped, Exley had tied the other end to DeLoach's manifold. Water slowed the block's fall, giving DeLoach just enough time to draw his knife and cut the line before it yanked him over the cliff. Exley blew out great bubbles of laughter.
As Eckoff tells the story, Exley turns a vivid red, grinning behind his mustache.
April 6, 1994
I stand in the hot wind, pointing a telephoto lens into Zacatón. I see Eckoff's face, and I put down the camera. The message is conveyed. The details, I know, will come later.
Bowden's rapid descent went smoothly, but his bottom mix of gases—the tank for the deepest portion of his dive—began to run out faster than he anticipated. At the 925-foot mark on his line, he began his ascent. (His two digital depth gauges later read maximum depths of 915 and 924 feet; a third gauge malfunctioned.) He didn't see Exley, but visibility was poor, and he assumed Exley had continued down to 1,000 feet. As Bowden made his first decompression stops, he realized that he was using gas faster than expected and that he might not be able to put in all the required decompression time.
Hundreds of feet above him waited support divers Karen Hohle and Ann Kristovich. (Kristovich, the team's medical officer, broke Eckoff's depth record with a 554-foot dive in Zacatón in September.) The two women saw Bowden's bubbles and knew he had begun his ascent, but there was nothing on Exley's line. Eckoff, who had just entered the sinkhole, saw worried looks on the faces of Hohle and Kristovich.
Where's Sheck? Kristovich asked on her underwater slate. Eckoff descended to 279 feet, the border of light and darkness. As she stared at Exley's vanishing line, she saw two tiny white squares drifting up toward her. Suddenly she realized they were the laminated pages of his dive profile, something he would never let go of alive. Somehow, she made it to the surface and out of the cave.
Bowden is not out of the water yet. He cut seven minutes off one decompression stop because of inadequate gas reserves; at another stop, a free-flowing regulator dumped out several minutes more. At about 250 feet, Bowden realized that he still had not seen Exley. At about 100 feet, Hohle told him in sign language what had happened. For the next few hours he would have to continue his decompression in terrible knowledge.
When he finally emerges in the night, Bowden will suffer his second case of the bends. Using a controversial French technique that proved effective with the first case, Kristovich will treat him with massive doses of intravenous steroids, anticoagulants and painkillers. By the next morning Bowden will be on his feet. He will continue deep diving, in Zacatón and elsewhere. Having reached at least 915 feet, Jim Bowden now holds the world open-circuit scuba depth record.
I assume that Exley's body will never be recovered, that he continued sinking from the point where the trouble occurred, whatever that trouble was. Zacatón will have to be a fitting tomb for the world's greatest cave diver.
I am wrong. Three days later, when the dive team begins to pull up Exley's unused decompression tanks, they discover him entangled in the guideline. His depth gauge reads 904 feet.
The exact cause of his death is unknown. There are several reasonable guesses, high among them HPNS, but they will remain only guesses. Irby Exley claims his son's body and has it cremated in just 21 hours.
April 12, 1994
I join divers from around the world for a memorial service at the Ortega Methodist Church in Jacksonville. The church bulletin contains an excerpt from Samuel Taylor Coleridge's Kubla Khan, one of Ex-ley's favorite poems. "Through caverns measureless to man/Down to a sunless sea," read the famous lines. The week before Exley went to Zacatón, his publisher had called to say that his latest book, his memoirs, had gone to the printer. The book's title: Caverns Measureless to Man.
After the service Don Jacobs, a 20-year-old who studied karate with Exley for seven years, sees me taking notes. "I want you to write this down exactly," he tells me. He thinks for a long minute before saying, "The man taught us to love and respect every individual no matter what race, religion, whatever, the way he loved each of us. He treated us like his own kids. Sheck Exley was the best friend I ever had."
I write it down, exactly as he says.
Exley set his distance and depth records—such as this dive to 780 feet in 1988—without fanfare.
Zacatón is so deep that Exley and Bowden's dive required dozens of tanks of various gases.
Bowden, whose gauges indicated different record depths, emerged with a severe case of the bends.
[See caption above.]
Exley had talked about retiring after his attempt at the world-record depth in Zacatón.
Michael Ray Taylor is a journalist and veteran caver who has written about cave exploration for SI.