SAO PAULO (Reuters) – Two men in Brazil are believed to have died from drinking local craft beer contaminated with a chemical compound used in antifreeze and other products, police in the state of Minas Gerais said on Wednesday.

Police investigating Brazilian craft brewer Backer found traces of diethylene glycol (DEG), a sweet-tasting solvent, in a beer vat used at the brewery in Minas Gerais state as well as in bottles of the brewer’s Belorizontina lager.

The Ministry of Agriculture said all products from the brewery had been recalled and production suspended.

The ministry said in a statement that its own analysis had found the toxic molecules in the water tank used by the brewery, rendering the contamination “systemic, or in other words, present in the Backer production process.”

The ministry called the contamination “exceptional.” It said investigators were working with three hypotheses: sabotage, leakage, and the misuse of a related chemical known as monoethylene glycol.

Backer said it does not use the diethylene glycol in its production process, but does use monoethylene glycol, which is less toxic.

Backer, in a statement posted on its website, said it was “cooperating fully with the investigations” as well as performing its own internal probe.

Backer has won international prizes and its beer is widely available in Brazil.

There have been 18 cases of reported DEG poisoning, police said in an emailed statement, with four of the cases confirmed. Cases have been reported since the beginning of January

One of the deaths was confirmed to have resulted from poisoning by DEG, while an autopsy is being performed to confirm the second.

(Reporting by Stephen Eisenhammer; Editing by Cynthia Osterman and Leslie Adler)