It was just a drop of liquid, just a tiny glistening drop. It glided over her glove like a jewel.

Scientist Karen Wetterhahn knew the risks: The bad stuff kills if you get too close.

She took all the precautions working with mercury in her Dartmouth College lab--wearing protective gloves and eye goggles, working under a ventilated hood that sucks up chemical fumes.

So on that sunny day in August 1996 when she accidentally spilled a drop, she didn’t think anything of it. She washed her hands, cleaned her instruments and went home.


It was just a drop of liquid, just a tiny glistening drop.

At first, friends thought she had caught a stomach bug on her trip to Malaysia. It wasn’t until she started bumping into doors that her husband, Leon Webb, began to worry. Karen, always so focused, always so sure of her next step, was suddenly falling down as if she were drunk.

In 15 years together, she had never been sick, never stopped working, never complained. Leon was stunned when she called for a ride home from work.

Over lunch a few days later, Karen confided to her best friend, Cathy Johnson, that she hadn’t felt right for some time. Words seemed to be getting stuck in her throat. Her hands tingled. It felt like her whole body was moving in slow motion.


“Karen,” Johnson said as she drove her back to the college, “we’ve got to get you to the hospital.”

“After work,” Karen promised, walking unsteadily into the Burke chemistry building for the last time.

That night, Leon drove her to the emergency room. It was Monday, Jan. 20, 1997, five months since she had spilled the drop in the lab. Just a single drop of liquid. But somehow it had penetrated her skin.

By the weekend, Karen couldn’t walk, her speech was slurred and her hands trembled. Leon paced the house. “Virus” seemed an awfully vague diagnosis for symptoms that were getting worse every day.


“It’s mercury poisoning,” Dr. David Nierenberg said. “We have to start treatment immediately.”

Leon hung up with relief. At last they understood the problem. Now maybe they could fix it.

*

It seemed impossible to believe that anything could be wrong with Karen Wetterhahn, one of those quietly impressive individuals whose lives seemed charmed from the start.


Serious and hardworking, she excelled at everything she turned to--science or sailing or skiing. She grew up near Lake Champlain in upstate New York in a family so close that when she and her only sister became mothers, they named their daughters after each other: Charlotte and Karen.

Karen was always the brilliant one of the family, the one who would do great things. And she did, becoming the first woman chemistry professor at Dartmouth, running a world-renowned laboratory on chromium research, devoting herself to her work.

It was important work, the kind that could lead to cures for cancer and AIDS. Karen thrived on it. She loved nothing more than experimenting with a chemical, figuring out its bad side and how it breaks down living things.

In the often cutthroat world of scientific research and ideas, where work is judged in academic journals and egos are as enormous as intellects, Karen stood out. Other professors would send their students to her office just to meet her. Talk to Karen, they would say. See how you can balance the demands of work and life and still be on top of your field.


The only place on Earth more precious than her lab was the dark cedar house that Leon, a mason, had built with his own hands. Home was Karen’s haven, her retreat from the rarefied halls of Ivy League academia.

Here, in the pretty village of Lyme, at the top of a hill at the end of a dirt road, she would listen to rock music--heavy metal was her favorite--and tend her garden.

Here, science came second to 12-year-old Charlotte’s baby rabbits, 14-year-old Ashley’s mountain bikes, Todd the goat and Dillon the pony.

At home, she would throw great neighborhood parties by the pool, or gather up the family and drag them off to the golf course, or the tennis court, or Ashley’s hockey game.


“We never knew she was a world-famous scientist,” one neighbor said afterward. “She was just Char and Ashley’s mom.”

Mercury poisoning.

Karen beamed when she heard the news. Finally, something she understood. Something she could explain. They would feed her fat white nasty-tasting pills that would flush the poison out of her system. Science would cure her, she told her husband, giddy with excitement as she sat in bed surrounded by her children and her notes.

“Karen was happy, so I was happy,” Leon says now. “We just didn’t know.”


How could they have known? Back in January, virtually nothing was known about the extraordinary dangers of dimethylmercury, the rare man-made compound Karen had spilled. Scientists didn’t know it could seep through a latex glove like a drop of water through a Kleenex. Doctors didn’t know it could break down the body over the course of a few months, slowly, insidiously, irreversibly.

Above all, no one knew how to stop its deadly progress as it cut off her hearing, her speech, her vision, reducing her body to a withered shell.

Today, because of Karen, the world knows so much more.

*


Quicksilver, as mercury is called, has long played a sinister game of seduction with science. One of the world’s oldest metals, it comes in various forms--some that heal, some that kill. Dimethylmercury, a colorless liquid that looks like water but is three times heavier, is far more toxic than other forms--the kind used in thermometers and batteries and medicine. It’s made purely for research and is rarely used.

Aug. 14, 1996. Just one shimmering drop. Now, six months later, Karen’s body was riddled with it.

Karen was the one who remembered the spill. It nagged away at her in the hospital as she underwent CT scans and spinal taps and tests for everything except chemical poisoning.

But I work with mercury, she said. Shouldn’t I be tested for the bad stuff?


The results plagued the doctors even more: Why had it taken so long for the symptoms to show? What kind of brain damage had already occurred? Had anyone else been exposed? Was she contagious?

And the question that still stings Leon’s heart, the one that still seems almost obscene: “Does your wife have any enemies?”

“Enemies!” he whispers incredulously through tears. “Karen didn’t have enemies. Everyone loved her.”

*


She was easy to love, this tall athletic woman with the deep infectious laugh. Comfortable to talk to. Always there for students, colleagues and friends.

And for Leon.

In some ways, they seemed an unlikely match: Leon, 40, the son of a Vermont dairy farmer who decided early on that masonry was more profitable than milking cows, and Karen, 48, the daughter of a chemist, the brilliant teacher and scholar. They had an easy comfort with each other. She would watch him coach Charlotte’s basketball team; he would accompany her on lecture trips to Italy, Norway and Hawaii.

“She was always interested in what I was doing,” he says often, as if he somehow has to explain.


He always knew her work was important but, since the accident, he has made an effort to really understand it. Today, he can recite her resume almost by heart: the awards she won as a doctoral student at Columbia, where her research on platinum was considered the most exciting of its kind, the Women in Science mentoring program she started at Dartmouth, the $7-million federal grant she won to study toxic metals.

She didn’t talk much about work at home, except the grant, the largest in the college’s history. “She was so proud of that,” he says.

The mercury research she was doing with Harvard and MIT was just something on the side, Leon explains. Chromium was Karen’s real area of expertise.

He shakes his head at the irony. Who could have imagined that the builder would eventually learn more than the scientist about the perils of dimethylmercury?


*

Others were learning too. At Dartmouth Medical Center, Dr. David Nierenberg scoured the medical literature for clues about how to treat his colleague and friend. A mile away in his campus office, two doors down from Karen’s, John Winn, head of Dartmouth’s chemistry department, grabbed every paper on mercury he could find.

The more her colleagues read, the more their hearts sank.

There was only one documented case of dimethlymercury poisoning this century, a Czech chemist in 1972 who had suffered the same symptoms as Karen and died. A handful of people had been exposed directly to pure methlymercury, another toxic mercury compound, and died. More well-known mercury poisoning epidemics, like those in Iraq in the 1970s and Japan in the 1950s, involved exposure to foods contaminated by methylmercury.


There was no telling if dimethylmercury would act the same way.

Karen herself was beginning to understand. There was a desperate look on her face as she pointed to the clock when it was time to take her pills. Still, she kept up a brave face, kept saying not to worry.

“Even if I don’t fully recover, maybe I’ll get well enough to ride again,” she whispered to her horse-riding friend and fellow scientist, Jacqueline Sinclair.

And when the hospital psychologist asked if she was depressed, she smiled. Wouldn’t you be? she replied.


That was Jan. 31, three days after the diagnosis. A week later, Karen was transferred to Massachusetts General Hospital for a massive blood transfusion that nearly killed her.

*

Leon was pacing at home again, torn between honoring his wife’s wish not to alert her parents and the feeling that she was sinking faster than she knew.

The phone rang. The nurse said Karen wanted to talk to her son.


From her hospital bed, the mother struggled. She drooled and moaned and the words just wouldn’t come. Ashley waited uncomfortably. He didn’t like the sounds. He didn’t like the silence. “Hi, Mom,” he coaxed, loud so she might hear. It was useless. The nurse ended the torture and took the phone.

“She just wanted to say goodnight,” Ashley says, bowing his head to hide the tears when he remembers the last time he talked to his mom. “She couldn’t even say goodnight.”

Others remember final moments too, although everything was happening so fast they didn’t seem like goodbyes at the time. But friends could see the toll on the scientist’s mind and body. They could see her faith fading, even as she continued to talk about being back on her feet for her new spring course. The day the ambulance came to take her to Massachusetts, she cried uncontrollably.

“I think that’s when she knew,” says Nadia Gorman, remembering how she tried to comfort her friend and colleague as she wondered if she would ever talk to her again. “There was a feeling of total tragedy in the air.”


In the ambulance, Karen told Cathy Johnson for the first time in their 15-year friendship that she loved her. In the hospital, she struggled to point to the letters “N” and “H” on her alphabet board. Leon nodded. He promised that, whatever the outcome, he would take her home, to New Hampshire.

“As a nonscientist, I couldn’t comprehend it all,” says Provost Jim Wright, Karen’s friend and former boss. “And the scientist I had been accustomed to turn to for answers was not available to help me.”

Doctors didn’t have answers either. They turned to Thomas Clarkson at the University of Rochester in New York, who had set up clinics in Iraq during the epidemic there in the 1970s, when hundreds of people died after eating mercury-poisoned bread.

His lab stopped everything to help, testing Karen’s hair and blood samples, ordering a batch of dimethylmercury to begin its own tests.


“I felt such a sense of helplessness,” Clarkson says. “Here was one of the world’s most distinguished scientists, and I was looking at this woman dying realizing there is nothing the scientific or medical communities can do.”

Karen’s lab was shut down. Her family, students and co-workers were tested. Her hospital room was checked for airborne mercury from her breath. Federal environmental and health agencies were alerted, as was the state health department. Her car and clothes and house were checked with mercury detectors.

E-mails flew around campus and across the country. Students emptied libraries of books on mercury, staying up all night to translate obscure research papers, seizing on any sliver of information they could find.

“There would be this elation when we found a study about someone that had been cured,” Gorman says, “then crying when we read that the end point for those who went into a coma was death.”


Scientists and doctors around the world offered their services.

“It was an extraordinary outpouring,” Nierenberg says.

But Karen was slipping too fast to appreciate it. Ten days after the diagnosis, on Feb. 7, she fell into a coma in Massachusetts. Leon told the doctors he was taking her home.

Back at Dartmouth Hitchcock, her family kept vigil by her bedside, her parents and sister talking to her as her body thrashed and moaned. Leon plastered the walls with cards and photographs: Karen on the golf course, at Disney World with the kids, lunch with her friends Cathy and Nadia, shaking hands with President Clinton at graduation ceremonies in 1996.


Just a tiny drop of poison. And she was fighting it with all her might.

It became too difficult for the children to visit. Even friends stayed home, waiting for the phone call that would tell them it was over.

Her husband stroked her face. Her sister and her best friend washed her hair. Doctors tried treatments never before attempted on humans.

But they couldn’t save her from the poison. On June 8, it took her life.


“She didn’t suffer,” Ashley told his eighth-grade class the next day. “She just stopped breathing.”

It was 10 months since she had spilled the drop in the lab, four months after she had slipped into a coma.

*

Karen Wetterhahn’s death was as extraordinary as her life and, in many ways, just as important. Perhaps she had an idea that it would be.


While she could still speak, she urged doctors and scientists to learn everything they could from her accident and to warn the world about the dangers.

The world has already learned so much. It learned that the gloves that were supposed to protect her actually acted as a conductor for the poison. It learned that dimethylmercury, so easy to order in research catalogs, is more deadly than anyone had imagined. Saddest of all, it learned that by the time the symptoms show, it is too late.

There is much more to learn, as scientists and doctors study her case. There will be studies and papers, symposiums and tributes. There may even be new federal regulations and mandatory blood tests for scientists who work with heavy metals. There is talk of banning dimethylmercury for good. And talk of turning her hospital room into a nurses’ lounge and naming it for Karen.

Her funeral took place on a hot summer day to the strains of a flute and a choir singing, “Be Not Afraid.”


In the packed college chapel, the sense of betrayal was as powerful as the sense of loss. Colleagues wept as they eulogized a modern-day Madame Curie who had sacrificed her life to her cause.

What good was pushing back the boundaries of human knowledge, they cried, if they had to bury one of their own?

Alone and bewildered, Leon sat in the front pew, looking out of place in his dark funeral suit, tears streaming down his face.

It all seemed like a dream, he says. No, he corrects himself--a nightmare.


He still wakes in the middle of the night and wonders if it’s true, or if Karen is just off on another trip. He still half expects her to come striding through the door with her laptop and her notes and her big smile to rustle up some tacos for dinner.

He picks up the picture of Karen working in her lab, a study of intensity in her goggles and gloves, staring at her test tubes and vials.

“She loved her work,” he says. “It made her happy.”

She couldn’t have known the risks. She couldn’t have known how bad the bad stuff really was. Truth is, no one knew.


Just a tiny drop of liquid. Sweet-smelling. Dense. Deadly.