In August 1996, Dartmouth College chemist Karen Wetterhahn, a leading researcher in toxic metal biochemistry, suffered a horrifying lab accident: a single drop of dimethylmercury landed on her glove. Despite following established safety protocols, the compound penetrated her skin—and set off a chain of irreversible events
Accidental Exposure: The Day Everything Changed
While preparing samples in a fume hood, Wetterhahn was using dimethylmercury—then a standard NMR reference material—to calibrate her instrument. Latex gloves were thought sufficient safety gear at the time. Unbeknownst to her, dimethylmercury could permeate latex nearly instantaneously, allowing the deadly toxin into her bloodstream within seconds.
The Slow Descent: Nonspecific Symptoms Emerge
For months, Wetterhahn appeared healthy. By November 1996, she began experiencing unexplained nausea, vomiting, and weight loss. Over subsequent months, her condition rapidly declined—manifesting as slurred speech, vision and hearing loss, and impaired coordination.
Diagnosis and Hospitalization
In early 1997, Wetterhahn was hospitalized and diagnosed with severe mercury poisoning. Her blood mercury levels exceeded 4,000 μg/L—over 4,000 times normal limits (typically 1–8 μg/L). Doctors confirmed the cause as her lab accident, backed by hair and blood tests.
Medical Efforts and Tragic Outcome
Her treatment included aggressive chelation therapy. Unfortunately, the mercury damage was irreversible. In February, Wetterhahn lapsed into a coma. Ten months after the accident—on June 8, 1997—she passed away at age 48.
Scientific and Institutional Legacy
The accident profoundly shocked the scientific community, exposing the grave limitations of lab safety protocols of the era. It prompted a re-evaluation of glove materials—leading to new guidelines recommending laminate barriers like SilverShield under durable outer gloves when handling volatile toxins. Federal agencies and institutions discouraged the use of dimethylmercury entirely and urged safer alternatives for NMR calibration.
Memorials and Continued Impact
To honor her memory, Dartmouth established the Karen E. Wetterhahn Graduate Fellowship in Chemistry and other awards supporting women in science. The National Institute of Environmental Health Sciences also created the Karen Wetterhahn Memorial Award, celebrating advances in environmental health.
A Catalyst for Change
Karen Wetterhahn’s tragic death ignited a shift in how scientists approach safety. Her case reminded researchers that even minute exposures to super-toxic chemicals can have catastrophic outcomes. Today, laboratories globally have updated their procedures and safety training to prevent similar tragedies.
Conclusion: A Legacy of Protection Through Awareness
Karen Wetterhahn was more than a victim of a laboratory misstep—she was a visionary scientist whose career spanned over 85 research publications, major roles at Dartmouth, and a groundbreaking toxic metals program. Her tragic death from dimethylmercury exposure—and the awareness it brought—has saved countless lives, reshaped lab safety standards, and continues to serve as a powerful reminder of science’s responsibility to protect researchers at all levels. Wetterhahn’s story continues to be taught in chemistry and toxicology courses as a case study in lab safety. Her legacy lives on not only in safer practices but in inspiring a new generation of scientists to prioritize rigorous hazard assessments. Her colleagues remember her as a brilliant, compassionate mentor who believed that scientific curiosity should never come at the cost of human safety.
