Roger Nelson has a simple and unequivocal message for the people of the year 12006: Don't dig here.
As chief scientist of the Waste Isolation Pilot Plant, Nelson oversees a cavernous salt mine that is the first geological lockbox for the "fiendishly toxic" detritus of nuclear weapons production: chemical sludge, lab gear and filters laced with tons of radioactive plutonium.
Nearly half a mile underground, workers push waste drums into crystalline labyrinths that seem as remote as the moon. A faint salty haze glows in powdery beams from miners' headlamps and settles on the lips like a desert kiss. Computer projections predict that within 1,000 years the ceilings and walls will collapse in a crushing embrace that seals the plutonium in place.
But plutonium remains deadly for 250 times that long -- an unsettling reminder that some of today's hazards will outlast the civilizations that created them. The "forever problem," unique to the modern technological age, has made crafting the user manual for this toxic tomb the final daunting task in an already monumental project. The result is a gargantuan system that borrows elements equally from Stonehenge and "Star Trek."
Communicating danger may seem relatively straightforward, but countless human efforts to bridge the ages have failed as societies fall, languages die and words once poetic or portentous become the indecipherable marks of a long-forgotten scribbler.
To future generations, warnings about Nelson's dump may seem as impenetrable as the 600-year-old "Canterbury Tales" are for all but a few scholars today.
"No culture has ever tried, self-consciously and scientifically, to design a symbol that would last 10,000 years and still be intelligible," said David B. Givens, an anthropologist who helped plan the nuclear-site warnings. "And even if we succeed, would the message be believed?"
The Energy Department predicted such a problem when it began planning for the $9-billion waste dump, dubbed WIPP, in 1974 and for a similar repository in Nevada at Yucca Mountain, near Las Vegas. That site has not yet been opened. Eventually it will store highly radioactive spent fuel from nuclear power plants as well as high-level waste from the weapons program.
Trying to communicate across 500 generations posed an unprecedented challenge of linguistics, semiotics and materials science, so the government first asked scientists, futurists and historians to envision what the far-distant future might be like.
Their report combines dry analysis and projections worthy of sci-fi disaster films, including massive climate change and feminist corporations that disbelieve WIPP warnings because they were written by men. Civilization is so interdependent and fragile, one panelist grimly noted, "that any massive global catastrophe might lead to reversion to at least a preindustrial era." Greed or desperation could give rise to legends that WIPP holds buried treasure -- apparently confirmed by surface warnings to keep out.
In a sense, they're right. Oil and gas deposits lie thousands of feet below the plant. In 100 or 5,000 years, an energy-poor government, company or gasoline-addicted tribe in a ruined society, like those depicted in the film "The Road Warrior," could adopt a "drill first, ask questions later" policy -- piercing the repository and pulling death to the surface.
Others predicted the invention of self-guided robotic "mole miners" that would penetrate the site from the side or below. In a scenario set in the year 11991, robotic slaves are infected with a computer virus that compels them to override their safety programming as they compulsively drill and construct mine shafts.
Opportunities for WIPP to fail, the experts agreed, are limited only by the imagination.
The government formed a separate panel of scientists, linguists and artists to create a warning scheme to counter the pessimistic projections. That group immediately rejected digital or paper records -- only a solution cast in stone could hope to solve a problem for the ages.
If Egyptian pyramids have lasted more than 5,000 years, today's monuments should fare better -- if built from prosaic materials, such as ultra-hard concrete. Scavengers stripped the pyramids bare for their once-shimmering marble skins.
The trefoil symbol for radioactive material might seem a natural alternative to text, but experts doubt that it will be understood by future societies any better than today's English. Consider the swastika, first used on pottery by European tribes in 4000 BC. It was adopted by ancient Troy and later became a holy icon of Hinduism. When the Nazis claimed it, the symbol became widely reviled.
The panelists also considered the plaque on the 1972 Pioneer space probe, now headed for deep space. It pictures a nude man and woman, a schematic drawing of the craft escaping our solar system and a basic interstellar map. They soon rejected it as a model, said Jon Lomberg, an artist who designed the plaque with the late astronomer Carl Sagan.
"You'd think it would be easier to communicate with humans" than extraterrestrials, he said. "But the [Pioneer] spacecraft will never land, so it's only going to be found by some highly developed technological culture. All we can guess about the future inhabitants of the area near WIPP is that they are human -- unless they are cyborgs.... Once you have people with augmented brains or genetically engineered minds with enhanced perceptions, you can't be sure how human they will be."
There are at least two universally understood pictographic forms. The human stick figure has survived nearly unchanged from Stone Age cave drawings to the doors of modern public restrooms. And the sequential panel, or comic strip, was developed independently by ancient Egyptians, American Indians and medieval Japanese.
They also are far from foolproof. The South Africa Chamber of Mines learned this when it used a simple picture sequence to train illiterate miners to clear rocks from mine tracks. Instead of improving, the rock problem worsened.
"Miners were indeed reading the message, but from right to left," said Lomberg, a former WIPP advisor. "They obligingly dumped their rocks on the tracks."
Nelson considers such concerns far-fetched, citing 30,000-year-old cave drawings.
"I understand those cave drawings and I don't speak Neanderthal.... He's killing a bison, 'bison -- food!' I can do pictographs just as well," he said. "I can convey an absolute sense of danger."
Yet the same Stone Age caves contain markings and handprints whose meaning remains obscure.
"The scribbles, we have no idea what they are.... The handprints -- is that the artist's signature?" Lomberg said. "We don't know. Of course the big difference is that these were not intended as messages to the future -- so far as we can tell."
With so many ways to fail, WIPP's planners opted for the classic American approach: Think big and leave no stone unturned. The plan will take more than a century to implement.
To grasp the scale of the warnings, start with the Great Pyramid in Egypt, built from more than 6.5 million tons of stone covering 13 acres. Multiply that mass by five, and you have the first warning layer: a 98-foot-wide, 33-foot-tall, 2-mile-long berm surrounding the site. That's just to get the attention of anyone who happens by.
"Size equates with importance. The bigger the animal the more that animal is to be reckoned with," Givens said.
Powerful magnets and radar reflectors would be buried inside the berm so that remote sensors could recognize the site as purposefully and elaborately designed.
It would be surrounded by 48 granite or concrete markers, 32 outside the berm and 16 inside, each 25 feet high and weighing 105 tons, engraved with warnings in English, Spanish, Russian, French, Chinese, Arabic and Navajo, with room for future discoverers to add warnings in contemporary languages. Pictures would denote buried hazards and human faces of horror and revulsion.
The same symbols would be printed on metal, plastic and ceramic disks with abrasion-resistant coatings, 9 inches in diameter, that would be buried just below the surface.
Three information rooms would archive detailed drawings of WIPP's chambers and the physics of its hazards on stone tablets. They would also provide a world map showing all other known waste repositories and a star chart to calculate the year the site was sealed.
One such room would stand in the center of the site. Another would be buried inside the berm, its only entrance a 2-foot hole to inhibit theft of the tablets, sealed with a 1,600-pound stone plug. The third room would be off site -- perhaps inside the nearby Carlsbad Caverns.
The final thing WIPP needs is a kind of Rosetta stone, a pictorial dictionary to aid in translation.
The markers will take decades to build and test, to help ensure they stand the test of time. But there's no hurry. WIPP won't be full until 2033. It would then be guarded by the Energy Department for 100 years until it is abandoned; no one who designed the markers would be alive to see them succeed for even a single day.
Inspired by so long a view, one of the site's expert panels, in an epigraph to its report, quoted Rabbi Tarfon, a Jewish sage who lived 1,900 years ago:
"You are not obliged to finish the task, nor are you released from undertaking it."
Once the vault is locked, some of WIPP's advisors want the site left unmarked because any warnings would draw only more attention, they say. Warnings, they argue, would be misunderstood or dismissed, the same way ancient grave robbers ignored curses inscribed on the tombs of Egyptian pharaohs to seize the riches inside.
Leave it bare, they contend, and the site will melt unseen into the harsh New Mexico desert.
"Any monument would become a tourist attraction," said Gregory Benford, a UC Irvine physicist and former WIPP advisor. "People come; they need hotels. Hotels need water. They drill for water and break into the vault. 'No marker' is a strategy, but people regard it as immoral."
Such views reflect WIPP's one certainty: No one knows what will happen far in the future.
"I have to assume that the divine creator is going to take care of most of this stuff," said Steve Casey, the WIPP engineer charged with overseeing construction of the warning system. "No matter what confounded thing we come up with, all it takes is one catastrophic event and it's gone."
That so much time and effort are spent even thinking about how to warn future generations reflects a significant shift in nuclear attitudes. The past still can be glimpsed a short drive from WIPP at a site where an atomic warhead was detonated 1,151 feet underground in 1961.
Two corroded plaques glued to a 4-foot concrete slab commemorate the test, dubbed Project Gnome. The monument has been nudged several yards over the decades by cattle that use it as a rubbing post. Spent rifle shells crunch underfoot; the pockmarked shrine is favored by locals for target practice.
A third plaque was pried off, perhaps as a souvenir. According to earlier visitors, it read, in plain English, "This site will remain dangerous for 24,000 years."