Methanol has been detected in the systems of each victim who died last month at a tavern in South Africa, according to officials.
Twenty-one teenagers died on June 27 at Enyobeni Tavern in Scenery Park, East London, according to the South African Police Service (SAPS).
Initial blood test results showed each victim had some level of the toxic chemical in their body at their time of death, Dr. Litha Matiwane, Eastern Cape provincial deputy director for clinical service, said Tuesday at a press conference in East London, via SABC News.
It is still unclear how much methanol was inside each of the teens' bodies, the doctor added.
"There is still progressive analysis of the quantitative levels of methanol and whether it could have been the final cause of death," Matiwane told reporters.
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Doctors have still not officially determined what caused the teens' deaths.
Levels of alcohol and carbon monoxide were also detected in some of the victims, Matiwane said.
Eastern Cape Premier Lubabalo Oscar Mabuyane called the victims' cause of death "a sensitive issue" and said they will only announce an exact cause when it is clear.
"It is only time that will make people heal," he said. "And we've got to give time for people to heal."
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Methanol is a dangerous form of alcohol commonly used as a solvent, pesticide, antifreeze and alternative fuel source. Exposure to methanol can result in a range of symptoms, according to the U.S. Centers of Disease Control and Prevention.
Those who ingest the chemical are also at risk for "a wide range of adverse health effects," per the CDC. Symptoms such as kidney failure and muscle death have been reported in cases of "severe poisoning."
Victims can also experience neurological symptoms (headache, dizziness, amnesia, coma, seizure, etc.), gastrointestinal symptoms (nausea, vomiting, severe abdominal pain, gastrointestinal bleeding, etc.) and visual symptoms such as blurred vision and blindness.