An investigation by police in a Brazilian state has found the contamination of beer which killed seven people was an accident likely caused by a manufacturing defect.

Almost 30 people were poisoned by diethylene glycol after drinking beer from the Backer brewery.

Police in Minas Gerais found a leak in a tank that started in September 2019. Eleven people linked to the company were indicted as part of the investigation but deliberate contamination was ruled out.

However, the Ministry of Agriculture, Livestock and Supply (Mapa) said tests indicate the presence of diethylene glycol and ethylene glycol in beers produced by Backer since January 2019, based on production reports provided by the company.

MAPA analyzed more than 700 samples from the brewery and in trade and found contamination in the Belorizontina, Capitão Senra, Backer Pilsen Export, Corleone, Capixaba, Três Lobos Pilsen, Layback D2 and Bravo brands. In 53 batches the presence of diethylene glycol or ethylene glycol was detected. Contaminated drinks were produced between July 2019 and January 2020.

A problem caused by a leak in a tank
A statement from Backer said the findings confirmed what it had already said; that it was an accident with no intention of causing harm. However, the company added this does not exempt its responsibility and it apologized to everyone and especially, victims and their families.

Company officials said it never bought diethylene glycol but did use mono ethylene glycol in the production process. A supplier in São Paulo is believed to have added diethylene to mono ethylene glycol. The accident was caused by a leak in one of 70 tanks, which had a manufacturing defect. A hole allowed the coolant liquid circulating in an external system to mix with the drink inside the container. It was a new tank, which started operating in early September 2019, according to Backer.

Earlier this year, the Brazilian Health Regulatory Agency (Anvisa) provisionally banned all Backer beers across the country with an expiration date from August 2020 onwards. The Três Lobos production site in Belo Horizonte was closed in January and the company laid off 50 people with another 150 on stand-by as it intends to shortly resume activities.

In June, the Minas Gerais State Department of Health reported that 42 suspected cases of poisoning by diethylene glycol had been reported. Of these, 36 were male and six female. Thirteen cases were /confirm/ied, four were discarded and 25 remain under investigation. Of the 13 confirmed cases, four died, five were discharged from hospital and four are still hospitalized.

In at least one of the deaths, the presence of diethylene glycol in the blood of a man was /confirm/ied. Five other men and one woman are also thought to have died.

Previously, 31 possible cases had been reported in March. Four were confirmed and 27 were being investigated but seven deaths were recorded. The increase of 11 intoxications from March to June includes three people now being counted that had not previously met the case definition as diglycolic acid was not detected in the sample. The other eight were added because of a change in the case definition going back to January 2018.