Tainted alcohol is the suspected cause of death of at least 19 adults in Costa Rica earlier this month, local officials confirmed this weekend.

The deaths, which reportedly occurred in San José, Cartago, Limón, Guanacaste and Heredia, appeared to be caused by methanol poisoning.

“Government officials confiscated more than 30,000 bottles of alcohol suspected to be tainted,” the ministry said in a statement on Friday, warning residents to avoid several brands that tested positive for contamination, ABC News reported.

The alcohol brands include Guaro Montano, Guaro Gran Apache, Star Welsh, Aguardiente Barón Rojo, Aguardiente Timbuka and Aguardiente Molotov.

Reports also stated methanol is known to be a poisonous alcohol found in solvents and antifreeze.

The symptoms of methanol poisoning include severe abdominal pain, headache and a lack of proper body movement coordination.

The World Health Organization stated in 2014, “Outbreaks of methanol poisoning occur when methanol is added to illicitly- or informally-produced alcoholic drinks.”

Costa Rica’s Ministry of Health posted an Expanding Health Alert over the weekend that was translated from Spanish.

“The Ministry of Health is carrying out the actions to reduce the exposure of consumers to the products adulterated, as well as related investigations, in coordination with other institutions, to determine the subjects related to this adulteration,” the alert said.

The ministry also warned, “Individuals or companies who are marketing adulterated alcoholic beverages are exposed to a variety of both administrative and criminal penalties.”

Dr. Devi Nampiaparampil, an associate professor at the New York University School of Medicine, said Monday she believes the tainted alcohol is probably a “manufacturing error.”

“Most likely this is related to some type of manufacturing error, that when they were trying to make ethanol they accidentally made some methanol. So that can happen in some counterfeit liquors.”

Nampiaparampil also said a person who consumes methanol might not realize it in the beginning.

“The problem with methanol is that it’s so much more dangerous than alcohol. It can make you blind, it can damage your kidneys and you might not even realize this at first and then you can die,” she concluded.