Laboratory safety requires more than just simple reminders. It is crucial for aspiring scientists to deeply understand and appreciate safety, drawing lessons from historical incidents, including tragedies, to improve protocols.
Despite its importance, lab safety is often overlooked. In educational settings, it can be treated as a mere formality, while professionals may compromise it due to pressures such as time, budget, or performance. Complacency from familiarity with procedures can lead to underestimating risks. However, safety should be a fundamental value integrated into all practices, not merely a reaction to accidents.
Mercury, a substance long synonymous with toxicity, once played a prominent role in various industries and medical practices. Though the phrase “mad as a hatter” originated from its use in hat felting, which ceased being used in the UK in 1941, mercury’s dangers still lingered for barometer and thermometer manufacturers, dental workers, and miners. It was even used in late 19th-century syphilis treatments, leading to the saying, “one night with Venus, then seven years with mercury,” reflecting the harsh side effects of mercury treatment.
However, the mid-20th century brought the devastating consequences of mercury poisoning into sharp focus, largely due to the events in Minamata, a small Japanese fishing village. From the early 1950s to the late 1960s, the Chisso Corporation’s acetaldehyde production, a chemical used in making acetic acid and synthetic rubber, released the toxic neurotoxin ethylmercury into Minamata Bay. This contamination entered the local food chain, resulting in severe neurological symptoms in both humans and cats, including convulsions, seizures, and walking difficulties. These symptoms became known as Minamata Disease.
It took time to connect the dots, revealing that mercury poisoning from bioaccumulation in fish and shellfish, caused by the Chisso Corporation’s waste dumping, was the culprit. As a fishing village, Minamata relied heavily on seafood, and the prolonged consumption of contaminated fish led to a devastating fatality rate exceeding 35%. Excavations revealed extraordinarily high mercury levels in the bay’s sediment, reaching 2kg per ton, enough to make it commercially viable to mine, if companies were inclined to make money from human suffering.
The Minamata Convention on Mercury is a global treaty adopted in 2013 to protect human health and the environment from the harmful effects of mercury. Named after the Japanese city of Minamata, where industrial mercury poisoning caused severe health damage in the mid-20th century, the convention aims to reduce mercury emissions and releases across its life cycle. It limits mercury use in products, industrial processes, and mining, and promotes safe storage, waste management, and monitoring. The treaty came into force in 2017 and has been ratified by over 140 countries.
Mercury has long been recognised as toxic in its organic, elemental, or inorganic forms. However, the tragic story of Professor Karen Wetterhahn serves as a stark reminder of the personal impact of such dangers. Her untimely death, due to a seemingly minor lab accident, underscores the need for unwavering vigilance in safety practices.
Professor Karen Wetterhahn’s journey began with a bachelor’s degree in Organic Chemistry from St. Lawrence University in 1970 and a doctorate from Columbia University in 1975. Joining Dartmouth College the following year, she channelled her experiences into increasing women’s participation in the sciences, co-founding Dartmouth’s Women in Science Project.
In 1996, during an experiment with heavy metal compounds, Professor Wetterhahn, at just 48 years old, encountered the devastating neurotoxin dimethylmercury. While studying its effects on cancer cells in vitro, she accidentally spilt two drops on her latex glove. Adhering to standard procedures, she removed her gloves and washed her hands thoroughly, noting the incident in the lab’s incident book before going home.
Within five months, she developed alarming symptoms, including unsteady gait, nausea, weight loss, and slurred speech. She was hospitalised in January 1997, where doctors noted that her symptoms resembled mercury poisoning. She recounted the minor incident with dimethylmercury, prompting urine and blood tests, which confirmed high mercury levels.
Her lab was immediately closed, and family and friends were tested. Testing of her office, bedroom, car, and frequent places found no traces of mercury, except the original dimethylmercury vial in her lab’s fume cupboard. Sadly, her condition deteriorated rapidly. The mercury severely affected her nervous system, and she fell into a coma three weeks after the initial exposure. Four months later, she passed away, her blood mercury levels 80 times the toxic dose.
Despite following all established safety procedures, including latex gloves, a fume cupboard, and hand washing, two small drops of dimethylmercury on her glove proved fatal. Research by the National Institute for Occupational Safety and Health revealed that dimethylmercury permeated latex gloves in under 15 seconds.
Many initially believed Professor Wetterhahn’s death was due to prolonged exposure to mercury salts, but the findings demonstrated the extreme lethality of dimethylmercury. While a blood mercury concentration of 10 micrograms per litre is normal, 50 micrograms per litre is considered toxic, warranting chelation therapy to remove the metal. Professor Wetterhahn’s levels were a staggering 4,000 micrograms per litre, making death inevitable.
Professor Wetterhahn’s tragic death highlights the critical need for strict lab safety protocols and awareness of risks, however minor. Continuous research into chemical interactions with safety equipment is vital to protect scientists. Her legacy should be one of vigilance and a commitment to safety education. Beyond the science, her story reveals the devastating cost of overlooked dangers, especially given her dedication to mentoring women in science. Her memory should inspire prioritising safety to prevent similar tragedies.
Lab safety is crucial and should be taken seriously. By learning from past incidents and maintaining high standards, we can ensure scientific work is done safely and responsibly.
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