A Sacramento woman went to the emergency room in July with numbness in her hands and feet, slurred speech and trouble walking.
The 47-year-old mother of five wasn't having a stroke or heart attack. She was suffering from mercury poisoning from a tainted anti-wrinkle cream imported from Mexico, KCRA-TV reported.
She has been in the hospital since then, according to her son, who told KCRA he wished to remain unidentified. His mother, who also hasn't been identified, was initially able to respond to verbal commands before she entered her semi-comatose state.
Olivia Kasirye, the public health officer for the Sacramento County Department of Health Services, told CBS Sacramento that the woman's cream contained methylmercury, a very toxic type of mercury.
This is the first time a methylmercury poisoning from face cream has occurred in the United States, the department said in a statement.
Kasirye is urging the public to immediately discontinue use of similar skin creams imported from Mexico because of how dangerous methylmercury is for adults and children.
"We don't know whether this was an intentional change or whether there was a mistake in the person who was adding the mercury," she said, telling the station that there's an informal network of suppliers who bring the altered skin creams into the country.
The most common way that people are exposed to methylmercury is through eating fish and shellfish that contain the toxin, according to the Environmental Protection Agency.
Skin exposure to methylmercury can affect the central and peripheral systems, with symptoms including tremors, memory loss and cognitive and motor dysfunction, according to the World Health Organization.
The average amount of mercury in blood is up to about 5 micrograms per liter as a result of mercury that is likely to be in someone's diet, according to the New York State Department of Health. The woman had 2,630 micrograms per liter in her blood, according to KCRA.